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Report of Progress 527, Kansas Agricultural Experiment Station, Walter R. Woods, Director
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DAIRY DAY -
1987
MANAGING THE HIGH-PRODUCING HERD
-
•
PART 2: "The Springer and Fresh Cow"
Morning Session 9:00
9:45
10:00
10:15
10:30
11:00
11:30
Manhattan Firestation Headquarters
Registration - View Poster Displays*
Refreshments - Courtesy of AMPI, MID-AM, and Kansas Mastitis Council
Welcome - Dr. Don Good
The College of Agriculture - Dean Walter' Woods
"Developing a High-Profit Herd" - Dr. John Shirley
"Dry Cow Management" - Mr. Jim Smith
"Periparturient Disorders in Dairy Cows" - Dr. Jeff Stevenson
"Feeding and Managing Early Fresh Cows" - Dr. Dick Dunham
Lunch -
KSU Dairy Club
Afternoon Session -
Manhattan Firestation Headquarters
1:00
Annual Meeting of Kansas Mastitis Council
Doug Forsberg, presiding
2:00
Quality Milk Awards - Bob Crawford, West Agro, Inc.
2:30
Tours (At your leisure):
1. Dairy Teaching and Research Center
2. Kansas DHI Laboratory, 628 Pottawatomie
3. Kansas Artificial Breeding Service Unit (KABSU), 1401 College Avenue
*Poster
1.
2.
3.
4.
5.
6.
7.
•
Displays:
Cow-side Milk Progesterone Testing
AI Repro-fresher Clinics
Selectronic Barn Sheets - mIlA
Inoculants for Various Silages
Yields of 79 Forage Sorghum Hybrids
Starch Utilization in Steers
Performance of Calves Fed Corn or Sorghum Silage
•
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FOREWARD
Members of the Dairy Commodity Group of the Department of Animal
Sciences and Industry are pleased to present this Report of Progress, 1987.
Dairying continues to be a viable business and contributes significantly to the total
agricultural economy of Kansas. Wide variation exists in the productivity per cow
as indicated by the production testing program (DHIA) in Kansas. About one-half of
the dairy herds in Kansas are enrolled in DHIA. Our 1987 DHI program shows that
tested cows average 15,396 Ib milk compared with 8,651 lb for all nontested cows.
This means that dairy cows enrolled in DHIA average more income-over-feed cost
($1,034/cow) than nontested cows ($537/cow). Much emphasis should be placed on
furthering the DHIA program and encouraginng use of its records in making
management decisions.
With our herd expansion program, which was begun in 1978 after we moved
to the new Dairy Teaching and Research Center (DT RC), we peaked at about 210
cows. The herd expansion was made possible by the generous donation of 72 heifers
and some monetary donations by Kansas dairy producers and friends. Herd
expansion has enabled our research efforts to increase, while making the herd more
efficient. Our rolling herd average is approximately 16,000 Ib, despite many
research projects that may not promote production efficiency.
•
The excellent functioning of the DT RC is because of the special dedication
of our staff. Appreciation is expressed to Bill Carinder (Unit supervisor), Jim Smith
(herdsman), Dan Umsheid, Mary Rogers, Charlotte Kobiskie, Bill Hanson, Robert
Resser, Don Allen, Mark Sellens, and Lloyd Manthe. Special thanks are given to
Neil Wallace, Natalie Brockish, Tammi DelCurto, and Cheryl Armendariz for their
technical assistance in our laboratories. A special thanks to Bill Carinder who,
after 8 years of service at the DT RC, recently left for a new job and greener
pastures in Iowa.
As demonstrated, each dollar spent for research yields a 30 to 50 percent
return in practical application. Research is not only tedious and painstakingly slow
but expensive. Those interested in supporting dairy research are encouraged to
consider participation in the Livestock and Meat Industry Council (LMIC), a
philanthropic organization dedicated to furthering academic and research pursuits
by the Department. More details about LMIC are provided later in this publication.
Appreciation is expressed to Charles Michaels (Director) and the Kansas Artificial
Breeding Service Unit (KABSU) for their continued support of dairy research in the
Department. Appreciation also is expressed to the College of Veterinary Medicine
for their continued cooperation. This relationship has enabled us to develop
cooperative research and establish an exemplary herd health program.
This Dairy Day Report is dedicated to Dr. Charles L. Norton who served for
19 years as Department Head and Dairy Industry leader in Kansas and for 10 years
as Professor of Dairy Science after the merger of the Department of Dairy and
Poultry Science with the Department of Animal Sciences and Industry in 1977. A
dedicatory citation for Dr. Norton is found on the next page. Thanks, Dr. Norton,
for your leadership to our industry.
•
J. S. Stevenson, Editor
1987 Report of Progress
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ii
DEDICATED TO
DR. CHARLESL. NORTON
•
Dr. Norton was born in Neponset,
Illinois. He received the B.S. degree
from the University of Illinois and the
Ph.D. degree in Animal Science from
Cornell University in 1944. He served on
the faculty of Cornell University from
1944 to 1947. He began his
administrative career as Head of the
Dairy Department at the University of
Rhode Island in 1947. He served as Head
of the Dairy Department at Oklahoma
State University from 1950-1958 and at
~
Kansas State University from 1958-1977.
I'
Since 1977, he has been serving as
Professor of Animal Sciences and Industry at Kansas State University, devoting
100% of his time to teaching, advising, and coaching the dairy cattle judging team.
He is an active member of numerous professional organizations including
Dairy Shrine, Gamma Sigma Delta, National Association of Colleges and Teachers
of Agriculture, Council for Agricultural Science and Technology, and the American
Dairy Science Association. He has been a member of ADSA since 1940. He has
served as a member of the Program, Resolutions, Nominations, and Membership
Committees. He also served as member and Chairperson of the Borden Award
Selection Committee and the Dairy Cattle Type Committee. He was elected to the
Production Division Offices and the Board of Directors. He also served as Advisor
to the Student Affiliate Division. On numerous occasions, he was a judge of
presented papers and evaluator of club yearbook and display entries at the national
meetings.
•
Dr. Norton has received several awards recogmzmg his outstanding
performance in teaching and advising. He was named the Outstanding Instructor in
Agriculture at Oklahoma State University in 1957, the Faculty of the Semester at
Kansas State University in 1978 and in 1984, and the Dedicatee, Little American
Royal at Kansas State University in 1977 and in 1986. He was awarded the Faculty
Award of Merit by Gamma Sigma Delta in 1983. The Student Affiliate Division of
the American Dairy Science Association named him Outstanding Advisor in 1977.
Dr. Norton has taught numerous courses, ranging from introductory animal
science to various areas of dairy production, and to dairy cattle judging and senior
seminar. He serves as Advisor/Counselor, as Advisor to the Dairy Science Club and
as Coach of the Dairy Cattle Judging Team. Dr. Nor'ton is an approved judge for
all breeds of dairy cattle and was formerly a classifier of Brown Swiss cattle.
.:
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iii
Dr. Norton has a superb knowledge of the dairy cattle industry. This
knowledge, blended with a sincere, gentle, caring manner, and seasoned with a
touch of wit and good humor, makes the learning process exciting and more
meaningful. Dr. Norton shows respect for each student, which, in turn, causes each
student to respect and admire him. He possesses a unique gift of encouragement
that makes each person try to do his or her best.
The advise and counsel of Dr. Norton has had a profound and positive
influence on the attitude, direction, and development of many persons whom he has
coached, taught, or advised. As one of his former students stated "his advice and
counsel were not always easy to accept, but they were always honest, fair and in
the best interest of each student."
We will miss Dr. Norton's presence in our day-to-day activities in the
Department. We wish him and his wife, Audrey, enjoyment in their retirement and
look forward to seeing them from time to time as they remain in Manhattan.
BIOLOGICAL VARIABILITY AND CHANCES OF ERROR
•
Variability among individual ani mals in an experi ment leads to problems in
interpreting the results. Although the cattle on treatment X may have produced
more milk than those on treatment Y, variability within treatments may mean that
the difference in production between X and Y was not the result of the treatment
alone. Statistical analysis lets researchers calculate the probability that such
differences are from treatment rather than from chance.
In some of the articles that follow, you will see the notation "P<.05". That
means the probability of the differences resulting from chance is less than 5%. If
two averages are said to be "significantly different", the probability is less than
5% that the difference is from chance or the probability exceeds 95% that the
difference resulted from the treatment applied.
Some papers report correlations or measures of the relationship between
traits. The relationship may be positive (both traits tend to get larger or smaller
together) or negative (as one traits gets larger, the other gets smaller). A perfect
correlation is one (+1 or -1). If there is no relationship, the correlation is zero.
In other papers, you may see a mean or average given as 2.50 + .10. The
2.50 is the mean or average; .10 is the "standard error". The standard error is
calculated to be 68% certain that the real mean (with unlimited number of animals)
would fall within one standard error from the mean, in this case between 2.40 and
2.60.
•
Many animals per treatment, replicating treatments several times, and using
uniform animals increases the probability of finding real differences when they
exist. Statistical analysis allows more valid interpretation of the results regardless
of the number of animals. In all the research reported here, statistical analyses are
included to increase the confidence you can place in the results.
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iv
CONTENTS
Dairy Day Program - 1987
inside cover
i
Foreward
Dedication to Dr. Charles L. Norton.
Biological Variability and Chances of Error •
.....
.....
ii
iii
•
Dairy Day Program Reports
Overview - Developing A High Profit Herd
Dry Cow Management Program • . • • • • •
Periparturient Disorders in Dairy Cows • •
Feeding and Managing Early Lactation Cows
...
......
I
2
5
13
Research Reports
Effect of Production on Reproduction • • . . . • • • • .
Concentrations of Progesterone and Conception Rates in
Holstein Heifers After heG Administration During the
First Three Weeks After Estrus . • • • • . • •
Gonadotropin-Releasing Hormone Improves Conception
Rates of Repeat-Breeders with Previous
Reproduction Disorders . • • • • . . • • • • • • • • . •
Influence of Prebreeding Progesterone Plus
Prostaglandin F -Alpha on Estrus and
2
Fertility in Lactating Dairy Cows • • • • • • • • • •
Further Studies Utilizing Hormones to Alter
Estrous Cycles and Fertility • • • • • •
Performance of Early Weaned Calves Fed Lasalocid
Effect of Supplemental Potassium and Buffer in
Starters for Early Weaned Calves • • • • •
•••••
Use of Extruded Soy Flour in Milk Replacers for Calves
Effect of Ruminal Protozoa on Performance of Early
Weaned Calves • • • • • • • • • • • •
Evaluation of A Calf Starter Supplement •• ••
Rumensin for the Lactating Dairy Cow • •
Glucose, Starch and Dextrin Utilization in the
Small Intestine of Steers • • • • • • •
Relative Feeding Value of Three Forage-Based
Diets for Holstein Heifers . . . • . • .
Mini-Reviews and Updates
19
A Look Around the Dairy Industry: Backward and Forward
USDA-DHIA Sire Summaries - AI Advantage
Early Lactation Somatic Cell Count Should Be Low . •
Update on Heat Detection Aids
.••.••••.•
Update on Gonadotropin-Releasing Hormone Treatments
for Repeat Breeders • • • . . . • • • • • . . • •
Cow-Side Milk Progesterone Testing • • • • . . . .
How Important Is Extra Solids-Not-Fat in Your Milk
Emerging Pathogens in Dairy and Food Products
Off-Flavors of Ultra High Temperature (UHT)-Treated Milk ••
57
63
66
68
Research in Progress
.........
Livestock Meat Industry Council (LMIC)
Acknowledgements
...........
21
24
26
29
32
35
39
41
44
47
49
54
70
72
74
77
78
80
84
85
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,
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OVERVIEW - DEVELOPING A HIGH PROFIT HERD
J.E. Shirley
Dairy Day - 1986 was the first of a 5-year series dealing with the
development of a high profit dairy herd. The program accented replacement heifer
management with respect to nutrition, reproduction, breeding, health, housing, and
some general management concepts. Dairy Day - 1987 stresses the dry and early
lactation period in a cow's production cycle.
Management implies that action is taken to control an event, whereas a
lack of management implies that an event occurs uncontrolled. Successful dairy
producers anticipate needs and act to provide those needs prior to an event.
Rather than reacting to an event, they act to control it in a positive way. To
correctly anticipate needs, one must have knowledge of the business and the desire
to continually assess and evaluate each element of the operation with respect to
its impact on the whole.
't
The impact of dry-cow management programs on subsequent lactation
performance has been quantitated and found to be of great significance. Equally
important to lactational performance are management programs for the
periparturient and early lactating cow. The condition of the cow when she begins
lactating and the presence or absence of disease during early lactation have a
direct effect on milk production and reproductive performance.
Dairy Day - 1987 presentations provide a positive approach to "Dry Cow"
and "Early Lactation Cow" management. Problem prevention is always a better
approach than problem solving.
•
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2
IE
••
DRY COW MANAGEMENT PROGRAM
J.F. Smith
Summary
Dry cows do not require the intensive daily management of cows in early
lactation, but the handling of mastitis treatments, feeding regimen, and grouping
are of utmost importance in determining how the cows will perform in the
subsequent lactation. The dry period is the time we allow for the cow to
regenerate milk-secreting tissue, combat mastitis, and prepare for the next
lactation.
The body condition of each cow should be moderate before drying off. Each
quarter should be treated with a commercial dry cow mastitis treatment, then the
cow should be separated from the milking herd for observation and fed a diet
specifically formulated for the dry period. The final stages of the dry period are
used to prepare the cow for acute changes that occur at calving, including
exposure to different feeds, and increasing grain intake 2 weeks before calving.
Increased grain intake during the final 2 weeks allows the rumen to adjust so
maximal intake of dry matter is achieved sooner after calving. This helps offset
the negative energy balance that dairy cows experience during early lactation.
Following these general guidelines during the dry period will decrease problems
encountered at or near calving, Which, in turn, will allow the cow to reach her
maximum genetic potential.
Background
Problems incurred at or near the time of calving greatly affect the
performance of cows. Dystocia, metritis, ketosis, displaced abomasum, milk fever,
fat cow syndrome, mastitis, and various reproductive disorders all restrict a cow
from reaching her maximal efficiency. Properly identifying these obstacles and
designing a plan of action unique for each herd are essential because no two herds
are alike. The feeding and management of the dry cows has great bearing on how
well they perform in the subsequent lactation.
General Guidelines of a Dry Cow Program
A good dry cow program must begin before the expected dry date. The dry
period should be used for maintaining body condition and as a recuperation
period between lactations. Moderate body condition should be attained during late
lactation, not during the dry period. The dry period is the proper time to generate
body stores because of higher feed efficiency. However, restricting energy intake
in late lactation is necessary at times to avoid overly fat cows entering the dry
period. But, it is important to remember that feeding below maintenance
•
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3
requirements during the dry period to reduce body stores can be harmful to the
cow and the development of the fetus. Determine a dry-off date from breeding
records or pregnancy exams and stay in the range of 46-65 days. Reducing dry
periods to fewer than 40 days does not allow enough time for milk-producing cells
to regenerate in the mammary glands. Longer than 80 days increases the chances
of clinical mastitis and metabolic disorders. Your goal should be 50-60 days. Cows
that conceive before 85 days postpartum should be dried-off near the 60-day mark
and those that conceive after 85 days, nearer the 50-55 day mark. On the day of
dry off, the cow should be milked out completely and treated in each quarter with
an approved dry cow antibotic infusion treatment using good sanitary procedures.
Flexible collodion for the final teat dip sets up a more lasting barrier to help
decrease rate of re-infection during the critical first 2 weeks of the dry period.
Dipping teats twice a day for the first 10 days of the dry period also helps
prevent re-infection, but is not always practical. After dry treatment, cows should
be moved from milking herd into a separate pen for dry cows, where they are fed
separately from the milking herd and observed daily. Problem cows with mastitis
should be remilked and retreated as necessary. The feeding program should meet
the maintenance requirements of the cow and unborn calf. Severe deficiencies or
excesses of energy, protein, minerals, or vitamins can result in more metabolic
disorders at or near ti me of calvi ng.
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The nutrient requirements for dry cows are summarized in Table 1. The best
feed for dry cows is long, dry hay, gr'ass, or cereal hay. Alfalfa should be avoided
because of its high calcium content that predisposes the cow to milk fever at
cal ving ti me. Dry cows need only 0.97 lb salt per day, whi ch can be provided in
the grain mix that supplements the hay. If more salt is fed, it can lead to
excessi ve udder edema. Allowing dry cows free access to granular salt and
minerals can lead to a dietary imbalance. Supply the proper amount of nutrients to
meet their requirements with forage and a grain mix that has the mineral package
to complement the forage.
Table 1.
Nutrient requirements of dry cows
Ingredient
•
Protein, % D.M.
NE L , Mcal/lb D.M.
ADF, %
NDF, %
Calcium, %
Phosphorus, %
Trace Salt, %
Vitamin A, U/lb D.M.
Vitamin 0, U/lb D.M.
Vitamin E, U/lb D.M.
First 6 weeks
Body Condition 4
Thin
11
0.50
27
35
0.45
0.35
0.25
1500
750
0.65
24
32
0.45
0.35
0.25
1500
750
7
7
11
Last 2 weeks
12
0.65
24
32
0.45
0.35
0.25
1500
750
7
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4
About 2 weeks before expected calving date, grain intake of the cow should
be gradually increased to a total of 1% of her body weight by the day of calving.
The other consideration during the warmup period is introducing any ensiled feed
currently fed to the milking string. Warming up or challenge feeding the dry cow
allows the rumen microbial population to adjust to the higher grain intake and
fermented feed that will be fed at freshening.
Cows should be observed closely prior to calving for problems such as
severe edema, swollen quarters, or going off feed. At time of calving, the cow
should be isolated to a clean, freshly bedded maternity pen, and assistance
should be rendered if needed. Immediately after calving, worming of the cow
should be performed to remove internal parasites. If mastitis is a problem at
fresheni ng and handling of the nearly term cow is possible, pre-di pping for 10-14
days before calving will aid in preventing new infections. At Kansas State
University, the dry period is also the time when we vaccinate our herd. This point
should be discussed with your local veterinarian to determine its feasibility in your
herd.
•
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5
a
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PERIPARTURIENT DISORDERS IN DAIRY COWS
J.S. Stevenson
Introduction
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The economic climate in the dairy industry requires producers to operate
efficiently to remain competitive. Attention to details and understanding of
reproduction, metabolism, digestive functions, milk secretion, and all aspects of
husbandry are essential. To be successful, producers must minimize reproductive
failure because reproductive performance affects the quantity of milk produced per
cow per day of herd life, the number of potential replacements needed to maintain
a constant herd size, and the longevity of the cow in the herd. In practice, this
translates into well-designed programs of herd health, milking, feeding, and
reproductive management that minimize involuntary culling of. problem cows by
maintaining healthy, profitable cows. The purpose of this review is to focus on the
interrrelationships of various peri parturient disorders in dairy cows and highlight
their collective impact on reproductive performance, milk yield, and predisposition
to other diseases.
Peri parturient Health
The term IJ periparturient" stems from the word "parturition" and the prefix
"peri," which literally but vaguely means "around." This phase generally includes
the dry period and the first 3 to 4 weeks after calving. The milk-secreting and
future reproductive capability of the dairy cow is related to peri parturient events.
Parturition is one of the most critical stages of the reproductive cycle and is a
period of significant death rate, as well as potentially severe debilitating injury to
dam and newborn calf. Future efficiency of reproduction and milk yield can be
affected adversely at this time. Therefore, major efforts should be directed toward
minimizing health problems that generally arise during the peri parturient period.
Keeping cows healthy is one of the most important steps in maintaining
good fertility and efficient mill< yield. Healthy cows produce more milk, rebreed
sooner, and have lower culling rates than their unhealthy herdmates. An example
of the reproductive performance of healthy cows from eight dairy herds is
illustrated (Table 1). Healthy cows were first bred at about 70 days, had
conception rates greater than 55%, had fewer than 100 days open or 382-day
calving intervals, and were culled at rates less than 1296. Good sanitation and a
herd-health program designed to maintain healthy cows was essential to this
achievement. Studies have shown that herd health programs return added profit to
dairy producers, even though veterinary costs per cow increase. Some of the
peri parturient disorders that are described below can be pl'evented and/or reduced
by careful management and cooperation between veterinarian and producer.
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6
Table 1.
First lactation
Trait
No. cows
Days to first estrus
Days to first service
Conception at first service, %
Days open
Services per conception
% culled
% culled for reproduction
Source:
.'
Reproductive performance of healthy dairy cows
Later lactations
69
134
50
55
70
68
59
95
1.6
4.4
1.5
Adapted from Oltenacu et al.
71
84
1.4
11.2
4.7
1984. J. Dairy Sci. 67:1783.
Dystocia or Calving Difficulty
Incidence of dystocia is about 6% (Table 2). While dystocia is primarily a
function of the size of the calf and pelvic area of the dam, other factors related
to the calf, dam or sire, nutrition, season, disease, and endocrine aspects are
implicated.
Calving difficulty is increased with large birthweight calves, male calves,
twins, malpresentations, stillbirths, heifers and young cows, lack of energy
consumed during the dry period, and fall and winter months of the year.
The implications of dystocia on disease, culling, milk yield, and reproduction
are many. Dystocia generally increases the risk of retai ned placenta, metri tis,
culling, death, milk fever, and cystic ovaries. Cows that have had dystocia have
longer calving intervals and produce less milk during the first month of lactation.
Cows that require surgical delivery of a dead claf at parturition generally
experience a 5 to 9% loss in milk yield.
Twinning
TWinning occurs about 3% of the time in dairy cattle (Table 2). Factors
that alter the rate of twinning include breed, season, cow family, age, and
inbreeding. Twinning increases with age of the cow, during fall and spring months,
and in certain cow families, where daughters of twinning cows will produce more
twins themsel ves than daughters of cows that never twinned.
Cows that bear twins have increased risk for stillbirth, retained placenta,
metritis, displaced dystocia, abomasum, culling, aciduria and ketonuria. Subsequent
reproductive performance is impaired as calving intervals are prolonged and milk
yield is decreased slightly after birth of twins.
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7
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Table 2.
Incidence of common periparturient disorders summarized from the
literature
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Disorder
Dystocia
Twinning
Stillbirth
Retained placenta
Cysti c ovarifs
Anovulation
Reproductivi tract
infections
Metritis
Milk fever
Ketosis
Displaced abomasum
Mastitis
3
Abnormal health status
Unweighted
mean, %
No.
references
Range
No.
calvings
No.
herds
5.8
3.3
4.1
9.4
12.3
5.5
0.9-13.7
1.6-5.8
1.4-6.3
2.0-17.8
3.0-29.4
2.3-22.5
40,828
56,470
45,835
>55,000
>20,00
15,918
218
2,265
2,264
>225
>196
130
8
6
4
11
9
11
17.4
21.3
5.9
5.4
1.4
6.9
36.9
8.5-24.2
10.7-36.4
1.4-10.8
3.5-7.4
1.2-1.7
2.3-16.8
19.9-81.6
13,271
>15,167
40,568
4,249
15,808
28,730
2,933
137
>60
161
63
103
123
17
3
5
6
2
4
4
7
1Delayed intervals to first postpartum ovulation longer than 4 wk postpartum.
2Yariously combined specifically diagnosed infections of the reproductive tract.
3lncludes cows with one or mOl'e disorders listed above.
Stillbirth
Occurrence of stillbirth is about 4% (Table 2). Stillbirth generally refers to
birth of a dead fetus; however, a broader definition is often used to include calves
found dead at calving (some of which may not have been truly stillborn). The
highest risk for stillbirth is in heif ers and young cows and may result from an
oversized fetus, overly fat dam, and increased incid~nce of twinning.
Cows with stillbirths have increased risk for a prolapsed uterus, retained
placenta, metritis, aciduria, and displaced abomasum. No evidence has been found
for direct relationships between stillbirth and milk yield or reproductive
performance.
Retained Placenta
Incidence of retained placenta is about 9% (Table 2). Retention of the
placenta or fetal membranes for 8 to 12 hr and up to 24 hr in some studies is the
definition generally used for retained placenta. Causes of retained placenta include
deficiency of selenium, vitamin E, vitamin A, B-carotene, and protein during the
late dry period. Increased placental retention occurs as cows age and at calvings
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8
during warm seasons and periods of extreme heat stress. Occurrence of indu~ed
parturition, twinning, milk fever, ketosis, dystocia in heifers, and increased calvIng
difficulty in all cows are associated with increased risk for retained placentas.
Retained placentae often lead to serious infections of the reproductiye
tract and increased risk for ketosis, displaced abomasum, culling and death. MIlk
yield following placental retention is slightly reduced in some cases, as well as
reproductive performance. Calving intervals are prolonged and pregnancy rates are'
decreased. Much of these effects on reproduction are indirectly manifested through
the increased rate of reproductive tract infections that follow placental retention.
Cystic Ovaries
Occurrence of cystic ovaries is about 1296 (Table 2). This would include
both types of cysts that predominate in dairy cows, the thin-walled or follicular
cyst and the thick-walled or luteal cyst. Peak occurrence is between 31 and 60
days after calving, in which 4796 of the diagnoses are made. Cysts are likely to
occur in cows having a previous history for cysts. Although cystic ovarian disease
has a low heritability in dairy cattle, its incidence has been reduced in Sweden by
selecting against its occurrence in bull studs.
Incidence of cystic ovaries is increased with age, in winter months, during
periods of high nutrient intake (early lactation), and especially when cows have a
uterine infection. High milk yield does not cause cystic ovaries, which are more
likely caused by an endocrine imbalance. Possible endocrine causes include the lack
of LH and specific ovarian follicular receptors for LH and FSH, which bind the
gonadotropins to growing follicles in preparation for final follicular maturation and
ovulation.
Occurrence of cysts in cows increases the risk for culling and reduces
reproductive performance by prolonging calving intervals and reducing conception
rates. Milk yield appears to be higher in cystic cows compared with noncystic
cows. However, when yield is adjusted for the length of the calving interval, a
2.596 loss in milk yield is observed. The increased yield is a result of prolonged
lactation length in the absence of the negative effect of pregnancy on milk
production.
Anovulation
Anovulation (prolonged intervals to first ovulation and estrus) occurs in
about 5 to 6% of dairy cows (Table 2). Since most dairy cows first ovulate between
2 and 4 weeks after calving, any delay beyond 4 weeks is defined as delayed
ovulation or anovulation. Anovulation declines in its incidence with increasing age.
It is generally associated with poor general health of the cow, fatty liver, ketosis,
uterine infections, and delayed lIter'ine involution. Cows with the most negative
energy balance (inadequate feed intake and large loss in body weight) and those
prone to various metabolic diseases because of poor body condition are at risk for
anovulation. Reproductive performance is impaired because cows are slow to begin
estrous cycles, and, thus, have delayed conception and prolonged calving intervals.
There is no reported effect of anovulation on milk yield.
,
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9
Reproductive Tract Infections and Metritis
'I
I,
Incidence of infections of the reproductive tract is about 17% and where
metritis was specifically diagnosed, it occurred in about 21% of cows after calving
(Table 2). These types of infections affect the vagina, cervix and uterus and could
be diagnosed at any time after calving. Reproductive tract infections, and
specifically metritis, increase as cows get older and tend to occur most often after
summer and early fall caivings.
Several health problems increase the risk for uterine infections including
milk fever, retained placenta, displaced abomasum, ketonuria, and aciduria. In
addition, overly fat cows, twinning, stillbirth, prolonged gestations, induced
parturition, and dystocia generally increase metritis.
Milk yield losses of 2 to 5% are reported for cows with reproductive tract
infections. Reproductive performance is adversely altered because calving intervals
are prolonged, fertility is reduced, and anovulation becomes more common (in cows
with metritis). Reproductive tract infections and metritis increase the risk for
displaced abomasum, ketonuria, and aciduria in cows that also have a retained
placenta.
•
Milk Fever
Incidence of milk fever or parturient paresis is about 6% (Table 2).
Occurrence of milk fever increases when high-calcium feeds are offered during the
dry period. Older cows and all cows with high milk production are at greater risk
for milk fever. In some cases, increased risk of milk fever is associated with
metritis and retained placenta.
Prevention of milk fever by feeding low
calcium-containing feeds during the dry period is essential. Some studies suggest
that feeding high protein early in the dry period, lower levels oof phosphorus than
calcium in the dry period, and lead feeding in the late dry period will prevent milk
fever.
Milk fever generally increases the risk for dystocia, retained placenta,
ketosis, and mastitis, and tends to increase calving intervals and slightly reduce
milk yield (-.5%).
Ketosis
•
Reported incidence of diagnosed ketosis in dairy cows is about 5% (Table
2). Ketosis can occur as uncomplicated cases caused by feeding diets high in
energy (glucogenic) or by underfeeding (marked negative energy balance). Ketosis
also occurs as complicated cases where ketosis and one or more other diseases are
diagnosed in combination. Cows with a previous history of ketosis or those having
milk fever, displaced abomasum, or retained placenta are at increased risk for
ketosis. Overfeeding and long dry periods of excess feeding that lead to overly fat
cows increase cases of ketosis at and after calving. Although older cows have
greater risk for ketosis, most studies conclude that high milk production is not a
cause of ketosis.
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"""
10
A strong relationship exists between displaced abomasum and ketosis. It is
difficult to determine which factor leads to the other. In addition, of those cows
in one study with ketonuria (ketosis), 82% had at least one other concurrent
problem, most of which was metritis, displaced abomasum, and retained. placenta.
Whereas conception rates may be reduced in ketotic cows, there is no eVldence for
a direct effect of ketosis on milk yield.
Displaced Abomasum
Displaced abomasum occurs in about 1.4% of dairy cows around calving
(Table 2). About 26% of the time, it is diagnosed during the first 7 days after
calving, with 63% and 82% of the diagnoses made by the end of the second and
third weeks, respectively. Cows become more susceptible to displaced abomasum
with increasing age, particularly if it occurred previously in earlier lactations.
Except for high milk yield, many factors increase the risk for displaced abomasum
including uncomplicated ketosis, twinning, stillbirth, retained placenta, metritis,
aciduria, and ketonuria.
Milk yield in cows with abomasal retention is reduced by 1.4 to 9.8%.
Limited research indicates that cows with a displaced abomasum have more risk for
metritis, ketosis, and possibly reduced fertility as a result of various complications
associated with abomasal displacement.
Mastitis
Occurrence of periparturient mastitis is about 7% (Table 2). About 45% of
the cases of mastitis occur during the first 15 days after calving. Older cows are
at increased risk for mastitis. However, of those cases diagnosed within 48 hr
postpartum, first and second lactation cows were infected 1.4% of the time,
whereas third or greater lactation cows were infected 3.4% of the time. Limited
studies suggest that cows with ketosis and milk fever may be more suscepible to
mastistis than healthy cows. High milk yield or the potential for high yield does
not appear to increase the risk for mastitis. However, few data are available and
are limited to clinical cases in which cows were either treated locally or
systemically for mastitis. Subclinical cases, indicated by a possible intramammary
infection or elevated somatic cell counts in milk, have not been well studied to
determine the potential predisposing effect of high milk yield.
There is no evidence to suggest that mastitis directly influences
reproductive performance. Indirect effects are possible since cows with mastitis
may have other associated problems, which when variously combined, may decrease
health and reproductive performance. Cows with subclinical mastitis have
decreased milk yield; however, more research needs to be done during the
periparturient period to explain the interrelationships between mastitis, milk yield,
and other diseases or disorders.
f
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,
11
Abnormal Health Status
Many studies have examined the effects of variously combined health and
disease factors (abnormal health status) that potentially interact with milk yield
and reproductive performance. In those studies, many of the previous diseases or
disorders cited above were considered. In total, the average incidence of cows
with abnormal health is about 37%. This means over one-third of all cows suffer
from at least one or more health problems during the L?eriparturient period.
Any type of health problem increases the risk for culling or death by 2 to
5X. Cows in their first lactation are at greater risk to be culled than older cows.
Milk yield in abnormal cows with poorer health is less (up to 3% less in a 305-day
lactation), as well as having less fat during the first 50 days.
Reproductive performance of abnormal cows is reduced markedly. Table 3
illustrates the reproductive performance in one large herd in which cows with and
without previous reproductive disorders were contrasted. Every reproductive trait
was reduced, resulting in 21% of the abnormal cows never conceiving compared to
only 696 of the normal cows. For cows conceiving, calving intervals were 24 days
longer in abnormal than normal cows.
Table 3.
~.
Health status and reproductive performance in a large dairy herd
Trait
Normal
695
59
No. cows
Calving to first estrus, days
Calving to first service, days
Conception at first service, 96
Calving interval, days
Services per conception
Pregnancy rate, %
64
45
373
2.0
94
Abnormal
1
306
62*
66
29*
397*
2.6*
79*
Source: Stevenson and Call, unpublished data.
lCows were classified abnormal if one or more of the following were diagnosed:
retained placenta, cystic ovaries, prolonged anestrus, twinning or uterine infection
based on palpation or the presence of a purulent discharge at anytime, including
breeding.
*P<.05.
Conclusions
A summary of the effects of various peri parturient disorders on
reproductive performance and milk yield of the concurrent lactation is shown in
Table 4. All reproductive and metabolic disorders examined either directly or
indirectly decrease reproductive efficiency, except mastitis. Milk yield was only
i
I
L
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12
impaired significantly in cows that required surgical assistance at calving.
However, there are marginal losses of milk yield as a consequence of retained
placenta, metritis, or reproductive tract infections, or general, abnormal health
status. Of the metabolic disorders, only displaced abomasum significantly reduced
milk yield.
Most disorders occur as part of a complex, rather than appearing as a
single ab,normality. Cows with one disorder are at increased risk for other
disorders, including many metabolic or reproductive ones. It also appears evident
that actual milk yield or potential for high milk production does not predispose
cows to increased risk for any disorder examined, except milk fever. This is
encouraging, because milk fever may be the disorder that is most readily prevented
by good dry cow managem ent.
All research suggests that preventive measures that limit the incidence of
one disorder may decrease directly or indirectly the risk and incidence of other
interrrelated problems. More research is needed to better understand the cause of
these disorders, thus, allowing better designed preventive herd health measures to
be adopted on the farm to improve the general health and overall productivity of
dairy cattle.
Table 4.
Suggested implications of various disorders on reproduction and milk
yield during the lactation in which the disorder was detected
Disorder
Reproduction
Concurre1
milk yield
Dystocia 2
Twinning
Stillbirth 2
Retained placenta
Cystic ovaries
Anovulation
Reproductive tract infections
Metritis
1\1ilk fever
Ketosis
Displaced abomasum
Mastitis
Abnormal health status
Indirect decrease
Decrease
Indirect decrease
Indirect decr'ease
Decrease
Indirect decrease
Decrease
Decrease
Indirect decrease
Indirect decrease
Indirect decrease
Unknown
Decrease
First 30 d decrease
Slight decrease
Unknown
Possible -.4%
Possible -2.4%
No effect
Possible -2 to 5%
Possible -3 to 5%
Possible -.5%
No effect?
-1.4 to -9.8%
No effect?
Possible -3%
Source: Summarized from the literature.
livlagnitude of decrease is shown if at least one study identified such a possibility.
2Surgical delivery associated with stillbirth decreased milk yield by 5 to 9%.
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13
••
FEEDING AND MANAGING EARLY LACTATION COWS
•
J.R. Dunham
Summary
Feeding and managing dairy cows during the prepartum and early lactation
periods have more effect on total lactation yields than all other factors. It is
during this time that the pattern of milk production is established for the entire
lactation. The full production potential of high producing cows cannot be realized
unless these periods are given special consideration.
Introduction
•
.
The profitability of a dairy cow is closely related to the level of milk
production during the first 120 days of lactation. The next 120 days is usually a
break-even period, and the last 65 days of lactation will usually pay for feed
costs. Therefore, the goal for a profitable dairy should be to establish feeding and
management programs that will allow dairy cows to reach their full production
potential during early lactation.
Summit Milk Yield
Summit Milk Yield (SM Y) is an estimate of the peak of the lactation curve,
which is made by the DHI program. SLYlY is important, since the total lactation
yield is affected by its magnitude. In fact, total lactation yield increases
approximately 300 lb for each 1 lb increase in 8M Y. Any practice that will
increase SM Y will have a long-term effect.
The Stage of Lactation Profile (SOLP), which is reported on the DHIA Herd
Summary, indicates that cows decline in production level at a rather constant rate
of about 0.1 Ib/day, regardless of the SMY level. Therefore, high production in
late lactation cannot be expected, unless production was high early in lactation.
Figure 1 shows the relation between SM Y, SOLP, and Rolling Herd Average (RHA).
•
A comparison of the average SlVIY of heifers, other cows, and all cows as
shown on the DHIA Herd Summary in Table 1 illustrates the importance of feeding
and management programs to SMY. In high-producing herds, the SMY, as would be
expected, is higher than in low-producing herds. In addition, the difference
between average SM Y of heifers and cows in high-producing herds is greater. This
suggests that high- producing herds are fed and managed in a manner that will
allow cows to express their potential. Or, in low-producing herds, production of
cows is similar to that of heifers because of nutritional limitations. Hence, feeding
and management programs of early lacation cows are of critical importance.
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14
80
STAGE OF LACTATION PROFI LE
SUMMIT
MILK
YIELD
70
60
.....
..!l
'-'
:.L
-'
50
*
*
*
*
72
65
59
ROLLING
HERD
AVERAGE
50
18,361
:E
>- 40
16,262
<
14.386
-'
0
11,373
30
20
100 -
<100
200
>200
STAGE OF LACTATION-DAYS
Figure 1.
Comparison of Summit Milk Yield, Stage of Lactation Profile, and Rolling
Herd Average.
Table 1.
Comparison of Summit Milk Yield of first lacatation heifers, other
cows, and all cows with Rolling Herd Average (RHA)
Summit Milk Yield
RHA
First
Others
11405
14609
16160
17610
19744
41.4
50.8
53.9
57.6
63.6
53.6
66.3
71.5
76.7
84.6
All
Difference
Others - First
- lb 49.8
60.6
65.5
70.0
77.2
+
+
+
+
+
12.2
15.5
17.6
19.1
21.0
Dry Period
The dry period should be considered when reviewing feeding and
management programs for early lactation cows, since it will affect the next
lactation. Cows should be dry for 45 to 60 days. There is no advantage in cows
being dry longer than 60 days, but dry periods of less than 45 days in length will
lower production in the next lactation.
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15
Special attention should be given to first lactation heifers. Many heifers
will be milking almost as well at dry-off time as they were in early lactation, and
most will be milking better than the older cows (Figure 2). Therefore, it is always
tempting to milk the heifers a little longer at the end of lactation. If these heifers
are not given a long enough dry period to gain body condition, then the
performance in the second lacation may be disappointing.
I
I
90
STAGE
OF LACTATION
PROFILE
80
-'l
70
Ci
I'
~
..... 60
~
>-
.....
<:
0
50
40
._Heifers
0 ...£01o/c>
-.
....... ...'" ... ......
.!!eifers
"'1IIiit:....
_
.. ......
...;;::.:::...~'a-.........,---
0
~
.... 0.............
-e_
.....
-
-.....,;
30
RHA
1761 0
-:::-~ 11 4 05
4 .........
20~
<100
100-200
>200
STAGE OF LACTATION -DAYS
Figure 2.
Comparison of Stage of Lactation Profile of cows and heifers.
Cows should go dry in good body condition. A body condition score of four
on a scale of one to five would be ideal. Cows in this condition will have a
covering of fat over the entire body but not to the extent of being patchy around
the hips and pins. It is a good management practice to separate thin dry cows from
those that are in good condition and feed according to body condition.
Care should be taken to avoid over-conditioning dry cows, since many
postpartum problems are associated with fat cows. For this reason, corn silage is
not recommended for dry cows because of its higher than required energy content.
Also, alfalfa should be fed only in limited amounts to avoid milk fever.
A good dry cow feeding program should be based on a grass-type forage
with enough grain, protein, and mineral supplement to meet nutritional
requirements (Table 2).
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16
Table 2.
Nutrient requirements of dry cows
First 6 weeks
Body Condition 4
Thin
Nutrient
11
0.50
27
35
0.45
0.35
0.25
1500
750
7
Protein, % O.M.
NE~, Mcal/lb O.lV1.
AD , %
NOF, %
Calcium, %
Phosphorus, %
Trace Salt, %
Vitamin A, U/lb O.M.
Vitamin 0, U/lb D.M.
Vitamin E, U/lb D.lVl.
11
0.65
24
32
0.45
0.35
0.25
1500
750
7
Last 2 weeks
12
0.65
24
32
0.45
0.35
0.25
1500
750
7
The 2 to 3-week prepartum period is a critical time for adjusting cows to
the lactating cows' ration so that they will readily consume large amounts of dry
matter after calving. The rumen microbes need this time to adjust to the types of
forages fed and to high energy rations. This is particularly necessary if ensiled
forages are to be fed. Adaptation to high energy rations should be made by
increasing grain consumption up to 1% of body weight.
Cows and heifers in the prepartum period should be observed closely for
indications of mastitis. Those individuals showing enlarged quarters should be
milked before calving, and a treatment program should be initiated. In addition,
springers showing excessive udder edema should be milked on a regular basis before
calving. Prepartum milking will reduce intramammary pressUl'e and will alleviate
the accumulation of fluids in the mammary tissues. A good supply of colostrum
should be on hand for the calves of cows and heifers that have been milked
prepartum.
Early Lactation Feeding
The goal of early lactation feeding is to maximize dry matter intake as
soon as possible after calving. As indicated in Table 3, early lactation cows are
quite responsive to increased dry matter intake, which is important in improving
SMY.
Table 3.
Expected milk response to each additional pound of dry matter intake
Production
(lb/day)
42
98
40
60
80
100
1.7
2.2
2.2
2.4
1.7
1.9
2.0
2.2
Days Postpartum
154
210
- lb milk 1.6
1.7
1.8
1.8
1.4
1.5
1.5
1.6
266
1.0
1.3
1.4
1.4
t
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17
f
••
Early lactation cows should be challenged soon after calving with additonal
grain to meet their requirements for milk production. Limiting grain consumption at
this time will restrict the SM Y and thus total lactation yield. Table 4 lists the
diet specifications for early lactation cows. Using computerized feeders to measure
grain consumption, researchers have shown that cows will increase grain
consumption gradually after calving, if given the opportunity. If grain consumption
is limited for 2 weeks or more following calving, digestive upsets may occur when
additional grain is fed.
Table 4.
~.
Specifications for total ration dry matter for early lactation cows
Item
Amount
D.M./body cwt.
Forage D.M./body cwt.
NE
Pr6tein
Crude Fiber
Acid Detergent Fiber
Neutral Detergent Fiber
Calcium
Phosphorus
Buffer
Trace Mineral Salt
Vitamin A
Vitamin D
Vitamin E
3.7 lb
1.5 lb
0.72 McaVlb
18%
12%
15%
28%
0.7%
0.45%
0.75%
0.25%
1500 U/lb
750 U/lb
7 U/lb
Managing the feeding program of early lactation cows is important in
maintaining cows on high energy rations. Buffer should be fed to prevent acidosis
and to keep cows on feed. Sodium bicarbonate or an equivalent amount of buffer
should be included at the rate of 1.5% of the grain mix .
.Yiaintaining adequate length of fiber is also necessary for keeping cows on
feed and for maintaining milkfat tests. Chopping forages less than 3/8 inch in
length can lead to digestive disturbances, since finely chopped forages will not act
as fiber in the rumen.
..•
:
Early lactation cows will respond to feeding high levels of protein. Since
most fresh cows have more ability to milk than eat, body weight is normally lost
during early lactation. This loss of body weight is a source of energy for milk
production, provided enough protein is fed. Table 5 indicates the production
response expected after increasing the protein percentage in the total ration dry
matter.
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Table 5.
Increase in milk production from changing protein percentage
Protein before
suppl em entation
1490
Protein after supplementation
16%
18%
19%
- lb 12%
14%
16%
18%
5.9
9.0
3.1
10.6
4.6
1.5
11.0
5.1
2.0
0.4
Other management practices can affect feed intake. Feeding more than
twice daily will provide fresher feed, which will be more readily consumed.
Separating first-lactation heifers from cows will reduce competition and allow
heifers to consume more feed. Providing fresh water within close walking distance
will also increase feed intake. Using tanks for watering in addition to automatic
waterers during hot weather may improve feed intake.
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19
a
••
EFFECT OF PRODUCTION ON
REPRODUCTION
E.P. Call
Summary
The genetic antagonsim that exists between production and reproduction is
overcome by sound management practices. Kansas Holstein herds were ranked by
quartile and analyzed by comparing various reproductive traits. Higher producing
herds suffered less reproductive loss based upon the factors considered. The most
significant differences concerned the average days dry, average days open on cows
not yet serviced, percent of cows open more than 120 days since fresh, and
average age at first calving. An adequate record system will identify potential
reproductive problems, and a sound Preventive Herd Health Program (PHHP) will
minimize actual losses from disease and cows not yet bred. All herds, regardless of
production level, would benefit by calving heifers at 24 mo.
•
Introduction
While dairy producers have long suspected that higher producing cows have
more reproductive problems, it was not until 1982 that Iowa State researchers
showed a genetic antagonism between production and reproductive characteristics.
However, research at the same institution demonstrated that the negative effect
could be overcome by sound management. Factors that contribute to reproductive
losses include: (1) days to first breeding, (2) days dry, (3) age at first calving, (4)
services per conception, (5) calving interval, (6) percent of cows not serviced by
120 days, (7) average days open for cows not serviced, and (8) disease and
nutritional entities. A sound Preventive Herd Health Program (PHHP) and adequate
records have been shown to be essential in minimizing reproductive losses.
Procedures
Holstein herds participating in the Kansas Dairy Herd Improvement Program
(DHIA) were ranked by quartile and summarized for various reproductive
parameters. These herds had rolling herd averages (RHA) as of February, 1987 and
reported reproductive information. Reproductive losses were calculated based upon
the following measurements as described in OyS 87-6, Focus on Dairy:
Repro-losses. Extension Dairy Science, Kansas State University, 1987: (1) calving
interval, (2), days dry, (3) services per conception, and (4) age at first calving.
•
While percent of cows not serviced by 120 days and average days open for
cows not yet serviced also contribute to reproductive losses in elongated calving
intervals, no measure could be applied to estimate the economic loss from these
factors .
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20
Results and Discussion
The data are summarized in Table 1. Ranking dairy herds by RHA is based
upon the long-accepted fact that higher producing cows convert feed into milk
more efficiently and, therefore, are more profitable. RHA is also an effective way
to rank herds to demonstrate the effect of production on reproduction but does not
identify specific or individual cow problems.
Surprisingly, reproductive losses per cow declined as RHA increased, with
the low quartile experiencing $152 yearly loss per cow) whereas the high group
averaged $109. There were no differences among groups for calving interval, days
to first service, and services per conception. Main effects were average days dry
and age of first-calf heifers. The obvious differences among the groups, which was
not included in the economic analysis, were the average days open for cows not
bred (124 to 77) and the percent of cows open more than 120 days (32 to 14).
Table 1.
Average reproductive characteristics of 582 Kansas Holstein herds with
42,365 cows grouped by level of rolling herd average (RHA). February,
1987
Rolling
Min.
herd avg calving
-milkinterval
(lb)
(days)
12,015
14,679
16,524
18,686
403
403
405
405
Calving to
first
service
(days)
85
81
81
80
(%)
37
31
28
27
Open cows
(days) (%> 120 days)
124
100
84
77
32
27
19
14
Reprod.
Services/
losses/
concep- Dry
period cow
tion
($)
(days)
1.8
2.0
2.0
2.1
73
67
63
60
e
152
140
124
109
f·
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21
a
••
CONCENTRATIONS OF PROGESTERONE AND
CONCEPTION RATES IN HOLSTEIN HEIFERS
AFTER hCG ADMINISTRATION DURING
THE FIRST 3 WEEKS AFTER ESTRUS
R.E. Stewart, M.O. Mee, and J.S. Stevenson
Summary
We conducted two experiments to determine the effects of administering
human chorionic gonadotropin (hCG) on day 4 or on days 15, 16, and 17 after
estrus on conception rates and progesterone secretion by the corpus luteum in
Holstein heifers. In the first experiment, 60 heifers received hCG or saline on day
Conception rates were similar between groups.
4 after estrus and AI.
Concentrations of progesterone were increased in treated pregnant and
nonpregnant heifers 7 and 14 days after treatment compared with pregnant and
nonpregnant controls.
In the second experiment, 62 heifers received hCG or saline on days 15, 16,
and 17 after estrus and AI. Conception rates again were similar between groups.
Concentrations of progesterone were higher in treated pregnant heifers on days 16,
17, and 21 after estrus and in treated nonpregnant heifers on days 17 and 21
compared with pregnant and nonpregnant controls. We conclude that stimulation of
the newly formed or mature corpus luteum by hCG increased production of
progesterone without affecting conception rates.
Introduction
Human chorionic gonadotropin (heG) is luteotrophic (sustains the function of
the corpus luteum) in cows and increases progesterone synthesis by corpora lutea.
Since some studies have shown that concentration of progesterone after estrus and
AI tend to be higher in cows that remain pregnant than in those that keep cycling,
stimulation of the corpus luteum with hCG should have a beneficial effect on
conception rates. Early administration of hCG (3 days after estrus and AI) in one
Other
study increased progesterone without affecting conception rates.
experiments involving the administration of hCG 15 days after estrus have reported
increased progesterone, prolonged cycle dmation and increased pregnancy rate in a
low-fertility herd, but decreased pregnancy rate in a high-fertility herd. The
objectives of our study were: (1) to determine if production of progesterone from a
developing or mature corpus luteum is altered by administering hCG to bred
heif ers, (2) to determine if increased progesterone in bred heifers influences
conception, and (3) to ascertain if production of progesterone from a corpus luteum
is affected by the stage of luteal development and(or) the presence of an embryo.
Procedures
•
Estrous cycles of 122 heifers in two experiments were synchronized using a
two injection PGF 2-alpha scheme. In Exp. 1, 60 heifers received 5,000 IU hCG im
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""
22
(n=31) or 5 ml saline (control; n=29) once on day 4 after estrus (day 0) in November
1984 (n=17), March 1985 (n=17), Aprfl 1985 (n=l1), or January 1986 (n=15). Blood
collected prior to hCG or saline administration on day 4 and 7, 14, and 21 days
later was analyzed for progesterone.
In Exp. 2, 62 heifers received 1,000 lU hCG im (n=33) or 1 ml saline
(control; n=29) once daily on days 15, 16, and 17 after estrus in February (n=10),
April (n=19), July (n=14), or August (n=19), 1986. Blood was collected prior to hCG
and 1, 2, and 6 days after the first of three hCG treatments.
Results and Discussion
Exp. 1. Conception rates are summarized in Table 1. Conception of treated
heifers (55%) tended (P=.16) to be lower than that of controls (72%).
Concentrations of progesterone in treated and control pregnant heifers were
similar in blood samples collected before treatment on day 4 after estrus. However,
treated pregnant heifers had higher (P<.Ol) progesterone than pregnant controls 7
days (6.3 + .5 vs 2.6 + .4 nglml) and 14 days (6.2 + .5 vs 5.1 + .4 ng/ml; P<.10)
after treatment. Concentrations of progesterone
serum were similar in both
groups 21 days after treatment. Nonpregnant treated and control heifers also had
similar concentrations of progesterone prior to treatment on day 4. Progesterone in
treated nonpregnant heifers was higher (P<.Ol) than in nonpregnant controls 7 days
(7.0 + .5 vs 3.8 + .6 nglml) and 14 days (6.2 + .5 vs 3.7 + .6 nglml) after
treatment. Progesterone concentrations were similar between treated pregnant and
nonpregnant heifers on the day of treatment and 7 and 14 days later. By 21 days
after treatment with hCG, pregnant heifers had higher (P<.OOl) progesterone than
nonpregnant heifers (5.7 + .5 vs 1.6 + .5 nglml) because of maintenance of
pregnancy.
m
Table 1.
Conception rates of heifers treated with hCG
postestrus
Trial
hCG
November 1984
March 1985
April 1985
January 1986
5/9
3/8
5/6
4/8
Treatment total
(56)
(38)
(83)
(50)
17/31 (55)*
or saline 4 days
Conception rate (%)
Saline
Trial total
8/8 (100)
7/9 (78)
4/5 (80)
10/17 (59)
9/11 (82)
2/7 (29)
6/15 (40)
21/29 (72)
38/60 (63)
13/1 7 (77)
*Tended to be less than saline-treated heifers (P=.16).
Exp. 2. Table 2 summarizes the conception rates in this study. Conception
rates were similar between hCG-treated heifers (67%) and controls (59%).
Concentrations of progesterone were similar between pregnant treated and control
heifers before first day of treatment (day 15 after estrus). On the second and third
f
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23
days of treatment (days 16 and 17), progesterone was higher (P<.05) in treated
pregnant heifers than in pregnant controls (4.5 + .2 vs 3.7 + .3 ng/ml and 5.4 + .2
vs 3.8 + .3 ng/ml).-On day 21 (4 days after the end of treatment), treated pregnant
heifersstill had higher (P<.OI) progesterone than pregnant controls (6.1 ~ .2 vs 3.7
~ .3 ng/m}). Concentrations of progesterone were similar in nonpregnant treated
and control heifers prior to initiation of treatment on day 15 and on the second
day of treatment (day 16). On days 17 and 21, concentrations of progesterone were
higher (P<.Ol) in treated nonpregnant heifers than in nonpregnant controls (5.5 .! .3
vs 3.4 + .3 ng/ml and 3.8 + .3 vs 1.3 + .3 ng/mI). Treatment with hCG also
apparently delayed luteolyslS in nonpr~nant heifers. Treated pregnant and
nonpregnant heifers had similar concentrations of progesterone on each day of
treatment, but on day 21 (4 days after the end of treatment) pregnant heifers had
higher (P<.OOI) progesterone than nonpregnant heifers (6.1 + .2 vs 3.8 + .3 ng/m})
- because of maintenance of pregnancy.
One-time stimulation of the newly formed (day 4) corpus luteum by hCG
(5,000 IU) increased production of progesterone but did not appear to affect
conception. Repeated daily stimulation of the mature corpus luteum by hCG (1,000
lU on days 15, 16, and 17) prior to luteolysis increased concentrations of
progesterone (and delayed luteolysis) without affecting conception rates of heifers.
Table 1.
<t
Conception rates of heifers treated with hCG or saline 15, 16, and 17
days postestrus
Trial
hCG
February 1986
April 1986
July 1986
August 1986
4/6
8/10
3/7
7/10
Treatment total
•
Conception rate
Saline
(67)
(80)
(43)
(70)
22/33 (67)
1/4
6/9
5/7
5/9
(25)
(67)
(71)
(56)
17/29 (50)
(%)
Trial total
5/10
14/19
8/14
12/19
(50)
(74)
(57)
(63)
39/62 (63)
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24
a
••
GONADOTROPIN-RELEASING HORMONE IMPROVES
CONCEPTION RATES OF REPEAT-BREEDERS WITH
PREVIOUS REPRODUCTIVE DISORDERS
J.S. Stevenson and E.P. Call
Summary
An experiment examinIng the benefit of treating repeat-breeders with 100
Ilg GnRH (Cystoreli n4!l) at the time of third or fourth insemination was conducted
in 513 dairy cows of which 93 (abnormal cows) had been diagnosed previously
(during the 60 to 90 days postpartum) as having reproductive disorders, including
retained placenta, uterine infections, prolonged anestrus, and cystic ovaries.
Treatment with GnRH improved conception in normal and abnormal repeat-breeding
cows by 13 percentage points or 42%.
Introduction
Three types of cows contribute greatly to long calving intervals in dairy
herds. These include: (1) cows that do not show estrus or are not observed in heat
until 2-3 months after freshening, (2) cows that are found nonpregnant at
pregnancy checks, and (3) repeat-breeding cows. Successful treatments for the first
two problems were addressed previously in our research at Kansas State University
(see pp 66-70, 1986 Dairy Day." KAES Rep. Prog. 506).
Use of GnRH (Cystorelin®) at the time of insemination has increased
conception rates of repeat-breeders in our previous work at KSU (see pp 26-27,
1984 Dairy Day, KAES Rep. Prog. 460). However, the mechanism of GnRH's action
in the cow is not well understood. Furtherm ore, the previous health status of cows
given GnRH at repeat breedings has not been documented to determine if it is less
healthy cows that respond to GnRH at insemination. The objective of our study
was to determine if GnRH would improve conception I'ates in cows with previous
reproductive disorders.
Procedures
From November 1985 to August 1986, cows (n=513) in one large commercial
dairy herd with (n=93) or without (n=420) previous reproductive disorders were
given 100 Ilg GnRH (i.m.) after insemination or were left untreated at third and
fourth services. Previous reproductive problems included retained placentae (26%
of abnormal cows or 4.7% of all cows), uterine infections (27% or 4.9%), cystic
ovaries (31% or 5.6%), and prolonged anestrus (16% or 2.9%). As cows were
diagnosed (during first 60 to 90 days after calving), various veterinary treatments
were employed to resolve the reproductive problem. Cows were not assigned
randomly to treatment, but were treated according to the discretion of the
herdsman or of any of three inseminators. Treatment was based on the knowledge
that GnRH might improve conception ['ates of repeat-breeders.
f
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25
Results and Discussion
Our results are summarized in Table 1. Treatment with GnRH tended to
improve (P=.13) conception rates from 12 to 25% in cows previously diagnosed with
reproductive disorders (abnormal cows) and increased (P<.05) conception rates from
36 to 47% in normal cows. Overall, conception rates improved by 13 percentage
points or 42% when GnRH was administered at the time of AI. The effect of health
status on conception rates was dramatic but not surprising, since conception rates
in normal cows (40%) were higher (P<.OOl) than those in abnormal cows (15%).
Table 1.
Treatment
GnRH
Conception rates (%) of repeat-breeders given GnRH with (abnormal)
or without (normal) prior reproductive disorders
Normal
Total
Abnormal
74/169 (44)a
68/145 (47)
6/24 (25)
Untreated
100/275 (36)
8/69 (12)
108/344 (31)
Total
168/420 (40)b
14/93 (15)
182/513 (35)
aDifferent from untreated cows (P<.05).
bOifferent from abnormal health status cows (P<.OOOl).
These results provide further evidence that GnRH is an effective treatment
for repeat-breeding dairy cows. A summary and updAte of all work utilizing GnRH
for treatment of repeat-breeders is found in this publication (pp 70-71). Although
it is not yet clear how GnRH improves fertility, fUI'ther work is underway to
better understand the physiology of GnRH's action.
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26
K
INFLUENCE OF PREBREEDlNG PROGESTERONE
PLUS PROSTAGLANDIN ~-ALPHA ON ESTRUS
AND FERTILITY IN LACTATING DAIRY COWS
••
M.O. Mee, R.E. Stewart, J.S. Stevenson,
and E.P. Gall
Summary
Progesterone administered before breeding may increase estrous expression
and subsequent fertility in lactating dairy cows. Holstein cows (n=302) were
assigned randomly at calving to three groups. Cows received no treatment
(controls), one injection of prostaglandin F 2-alpha (PGF), or progesterone plus one
injection of PGF (PRID + PGF). The average interval to estrus was 5 days shorter
in PRID + PGF cows compared to cows given only PGF. In addi tion, more cows
were observed in estrus 2 to 5 days after treatment in the PRID + PGF group
compared to the PGF group. Average days from calving to conception were
reduced in PRlD + PGF cows by 15 to 20 days compared to control and PGF cows.
We concluded that prebeeding progesterone in combination with PGF appears to
enhance fertility.
Introduction
Sever'al studies have attempted to synchronize estrus to a])ow for
convenient breeding of dairy cows at first service at approximately 60 days
postpartum. Most of these studies have used prostaglandin F 2-alpha (PGF) and a
few studies have incorporated progesterone plus PGF in estl'ous synchronization. A
previous attempt at the KSU dairy to synchronize estrus failed to show any benefit
of utilizing two injections of PGF given 11 days apart. Furthermore, there is little
information on the effects of progesterone in estrous synchronization. It has been
demonstrated that cows with increased progesterone levels in their blood during
the estrous cycle before breeding have better conception rates than herdmates
with lower progesterone levels prior to breeding. This suggests that progesterone
may have a prebreeding role for increasing fertility. Therefore, the objectives of
this study were: (l) to determine the feasibility of using one injection of PGF to
regress the corpus luteum (CL) prior to first service and (2) to examine further the
prebreeding role of progesterone prior to CL regression on estrous expression and
SUbsequent fertility.
Procedures
This study utilized 302 lactating Holstein cows in the KSU dairy herd. Cows
were assigned randomly at calving to three groups. Group 1 consisted of 112
control cows that were inseminated at the first observed estrus after 42 days
postpartum. Group 2 consisted of 97 POP cows given one injection of POF (25 mg
Lutalyse®) between 56 and 62 days postpartum. Ot'OUp 3 consisted of 93 PRW +
PGF cows. Cows in this group had a progesterone-releasing intl'avaginal device or
PRID inserted into the vagina at approximately 54 days postpm·tum. A PRID is a
CfI
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27
silastic coil impregnated with 1.13 grams of crystalline progesterone. The PRlDs
remained in place for 7 days with an injection of PGF (25 mg Lutalyse®) given 24
hI' prior to PRID removal. Cows in Groups 2 and 3 were inseminated at the first
observed estrus after Lutalyse®. This allowed for all treated cows to be
inseminated for the first service around 60 days postpartum.
Blood was collected at 0, 24, and 48 hI' after PGF injection and analyzed
for concentrations of progesterone in serum. This enabled us to monitor the
success of CL regression. Blood also was collected at the time of PRlD insertion
and removal.
Results and Discussion
As illustrated in Figure 1, more PRlD + PGF cows were observed in heat 2
to 5 days after PGF injection, resulting in a more synchronous estrus compared to
PGf cows. This result suggests that PRlD + PGF synchronizes more heats than one
injection of PGF. However, progesterone may be enhancing behavioral signs of
heat. Missed heats and PGF failure may have contributed to the wide distribution
of observed heats in the PGF group.
Effect of Treatment an
Estrus
40
~t
.:55
.:50
..
~
PCF2 -
alpha
PRID+PCF2-alpha
en
:::l
~
1n
25
w
.s
,.
en
20
0
(".)
'0
0 15
:z
10
5
0
Figure 1.
Distribution of heats after one injection of PGF or a 7-day
progesterone-releasing intravaginal device (PRID) and PGF 1 day
before PRlD removal.
2
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-------------------.~
28
t- ·
In addition, the average interval to estrus after PGF injection was reduced
(P<.05) from 16 to 11 days in the PRlD + PGF group compared to the PGF group.
Results of the reproductive traits examined are illustrated in Table 1. The
average interval to first breeding was 10 days longer in the PGF group compared
to controls. Conception rates were similar in all groups; however, in the PRlD
group, conception rates tended to be higher in those cows conceiving 2 to 5 days
after treatment compared to those conceiving 6 or more days after PGF (53 vs
32%). The reasons for this finding are unknown, but it could be related to the
stage of the estrous cycle when the PH-IDs were inserted and/or the failure of CL
regression after PGF administration. Interestingly, this effect was not observed in
the PGF treatment group, since conception rates were similar 2 to 5 days and
after 6 or more days (44 vs 46%).
The PRlD + PGF group averaged
group and 15 days fewer than controls.
were required in the PRlD + PGF group
between first service and conception
compared to the other groups.
Table 1.
20 fewer days to conception than the PGF
In addition, fewer services per conception
compared to the other groups. Fewer days
were observed in the PRlD + PGF group
Reproductive measures of cows after treatment
Item
No. cows
Interval to 1st service, d
Conception rates at 1st service, %
2 to 5 d, %
> 6d, %
First service to conception, d
Days open
Services per conception
Control
112
65
38
42
107
2.1
PGf
PRlD +
PGF
97
a
75
45
44
46
b
39
b
112
2.0
93
69
47
53
32
a
23
a
92
a
1.7
aDifferent from control (P<.05).
bDifferent from PRlD + PGF (P<.05).
The results of this study are preliminary, with further studies needed to
investigate the role of progesterone. Howevel', our data suggest that one injection
of PGF results in reproductive performance si milar to that of untreated controls
and, therefore, provides no economical benefit.
It appears that estrous
synchronization and fertility can be enhanced by administel'ing progesterone before
breeding in combination with PGF.
t
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29
R
FURTHER STUDIES UTILIZING HORMONES
TO ALTER ESTROUS CYCLES AND FERTILITY
••
J.S. Stevenson, R.E. Stewart, and E.P. Call
Summary
In one large dairy herd, we examined the reproductive performance of 943
cows following early postpartum hormonal therapy utilizing gonadotropin-releasing
hormone (GnllR or Cystorelin®) and prostaglandin F2-alpha (PGF). None of our
hormonal treatments improved reproductive efficiency in this herd, whereas earlier
studies at the KSU Dairy Teaching and Research Center had proved beneficial.
However, cows given PGF to induce estrus at the beginning of the breeding period
had similar reproductive performance to control cows, suggesting a potential use
for one injection of PGF to allow the breeding of more cows by a target date
after calving (e.g., by 65 days).
Introduction
Several studies have reported that GnRH, given between 10 and 18 days
after freshening, will:
(1) help the uterus return to normal more rapidly, (2)
shorten the interval to the cow's first ovulation after calving, (3) shorten the
average interval to the first observed heat, and (4) reduce calving intervals. In
addition, some reports suggested that PGF, when administered between 14 and 28
days after calving, will: (1) increase conception rates at first services and (2)
shorten calving intervals (see pp 40-42 in the 1985 Dairy Day, KA ES Rep. Prog.
484). The benefits of these hormonal treatments appear to be associated with
estrous cycles. A direct effect on the reproductive tract is suggested, but the
mechanism of therapeutic benefit is not well understood. The objective of this
experiment was to reaffirm our earlier work using a large commercial herd and to
determine if one injection of PGF given early in the breeding period could promote
improved calving intervals compared to nontreated, control cows bred as they
showed heat spontaneously.
Procedures
During the fall of 1985, 1,049 cows were assigned randomly as they calved
between September 23 and December 17 to five experimental groups: (1) GnRH
(l00 llg or 2 cc Cystorelin®) injected (im) once between 11 and 25 days
postpartum, (2) early PGF (25 mg or 5 cc Lutalyse®) injected (im) once between 11
and 25 days, (3) late PGF given once between 25 and 40 days, (4) breeding POF
given once between 48 and 59 days (beginning of the breeding period), and (5) no
hormonal treatment. All cows were milked 3X daily for 4 min and 15 sec. Breeding
began at the first observed heat after 40 days postpartum except for cows in the
fourth experimental group (breeding POF), in which inseminations were carried out
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30
after cows were given PGF and detected in heat. In the breeding PGF group, PGF
was administered 6 days after breeding began in each breeding group.
Results and Discussion
Results of this study are summarized in Table 1. Only 943 of the 1,049
cows (90%) treated were inseminated at least once. Intervals from calving to first
estrus and first service were unaffected bv hormonal tl'eatments. Most cows, on
the average, were first inseminated by 75 days postpartum. Calving to conception
intervals in controls averaged 100 days or projected to an acceptable 380-day
calving interval. Cows given one injection of PGF to initiate the breeding period
had calving to conception intervals of 105 days or 385-day calving intervals similar
to control cows. In contrast, treatments with GnRH and PGF prolonged conception
intervals by 11 to 21 days. We have not observed previously a detrimentAl effect
of these treatments and cannot explain why this occurred.
The remaining reproductive traits examined were similar among treatment
groups except for services per conception. Cows given the late PGF treatment (25
to 40 days after calving) tended to require more services and also had the longest
intervals to conception (Table 1).
Table 1.
Reproducti ve perform ance
Trait
GnRH
No. cows bred once
Calving to first estrus
Calving to first AI
Calving to conception
Conception at first AI, %
No. cows pregnant
Conception rate, %
Servi ces/ conception
211
69.1
72.6
111.7*
37.4
177
83.9
2.2
Early
Late
Breeding
PGF 2-alpha PGF 2-alpha PGF 2-alpha
215
71.4
76.7
111.7*
35.3
177
82.3
2.2
190
64.7
71.3
121.2*
35.3
159
83.7+
2.6
109
70.0
71.6
105.0
41.3
93
85.3
2.1
Control
218
68.3
72.2
100.4
41.7
189
86.7
2.0
* Different from control (P <.0 5).
+Different from control (P=.U9).
Other experiments have shown improvements for cows given GnRH at 8 to
18 days after calving. In addition to our recent data (see pp 40-42, 1985 Dairy Day,
KAES Rep. Prog. 484), reproductive performance of abnormal cows in New York,
and of cows with retained placentas in Ontario, was improved by Gn1tH when early
breeding was practiced.
Results of other studies, however, have not been quite as promising. In two
Colorado herds in which early breeding was practiced, treatment with 250 llg
GnRH improved fertility in only one herd. Another study in a Florida herd
,
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31
practicing 3X daily
(Buserelin®) had no
250 llg GnRH given
of uterine infection
milking also reported that various doses of a GnRH analogue
effect on reproductive performance. A Canadian study found
on day 15 to be detrimental because it increased the incidence
and irregular cycling - unless PGP was given 10 days later.
We are uncertain why GnRH or PGF treatments given early postpartum are
not consistently effective in all herds, but it is apparently due to a number of
factors including dose and management. It appears that consistent results are
possible when using doses of 200 to 250 llg GnRH in herds where early breeding is
practiced (starting at 40 to 50 days postpartum) and cows are milked twice daily.
1
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32
a
•
PERFORMANCE OF EARLY WliANED CALVES
FED LASALOCID
•
R.L. Anderson, T.G. N~araja, J.L. Morrill, 2
P.G. Reddy, T.B. Avery, and N.V. Anderson
Summary
Twenty-two newborn, bull calves were used to determine the effects of
lasalocid on growth and feed intake of early-weaned calves from week 1 to 12.
Calves were assigned to lasalocid or contl'ol groups on day 3. Lasalocid-fed group
received lasalocid in milk from day 4 to 7 and in milk and pre-starter from days 7
to 14 and in starter feed from weeks 2 to 12. Lasalocid-fed calves had a
significantly higher feed consumption and greater weight gain than calves that did
not receive lasalocid. The difference became apparent only after 6 wk of age.
Lasalocid appears to be a beneficial feed additive for newborn calves.
Introduction
Early weaning of dairy calves contributes to early development of ruminal
microbial activity because of increased intake of dry feed. Because of the rapid
development of ruminal microbial activity, it may be beneficial to feed ionophore
antibiotics to young calves. In addition to the benefits associated with altered
ru minal f erm entati ve characteristi cs, ionophore antibioti cs may also contribute to
the control of coccidiosis in growing calves. The effect of ionophore antibiotics
such as lasalocid on growth performance of newborn calves has not been previously
determined. Therefore, we incorporated lasalocid into milk and dry feed of calves
raised on an early-weaning program and monitored dry feed intake, growth, and
incidence of coccidiosis.
Procedures
Twenty-two Holstein bull calves were separated from their dams within 24 h
after birth and fed colostrum until 3 d of age. The calves were then divided into
two treatment groups, control or lasalocid-fed, and fed whole milk (8% birth wt.)
until weaned at 3 wk of age. Calves in both groups were fed a pre-starter diet
(Table 1) from d 3 until they reached a daily intake of 227 g. They were then fed
a mixture of 227 g of pre-starter daily and all the calf starter (Table 2) they
would eat until 6 wk of age, after which they wel'e given ad libitum access to only
the starter diet. Lasalocid-fed calves were given lasalocid (Bovatec® liquid premix,
20% w/w suspension, Hoffmann-LaRoche Inc., Nutley, N.J.) in milk at 1 mg/kg body
weight daily from d 4 to 7, and at .5 mg/kg body weight daily during wk 2. Calves
in this group had access to unmedicated pre-starter from d 3 to 7, but during wk 2
;Financial support was provided by Hoffmann-LaRoche Inc., Nutley, NJ.
Dept. of Surgery and Medicine.
,-1
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33
they had access to pre-starter containing lasalocid (88 mg/kg pre-starter). After 2
wk of age, lasalocid-fed calves were given medicated pre-starter (88 mg/kg
per-starter) and starter (44 mg/kg starter) diets. The lasalocid concentration in the
dry feeds was calculated to provide a daily intake of 1 mg of lasalocid/kg body
weight.
Daily feed intake and weekly weight gain of all calves were monitored from
birth to 12 wk of age. Feces of each calf were evaluated daily. Rectal fecal
samples were also obtained from each calf at 4, 8, and 12 wk of age, and examined
for coccidiosis.
Results
I
():
"
The body weights, weight-gain and feed consumption and daily intake of
lasalocid of calves are shown in Table 3. The body weights of lasalocid-fed calves
were significantly greater at 5, 7, 8, 9, 10, 11, and 12 wk of age than those calves
that did not receive lasalocid. Accordingly, weekly weight gains were higher for
lasalocid-fed than for control calves. Overall, lasalocid-fed calves weighed about
10 kg more than control calves at the end of the 12 wk period. Calves fed
lasalocid consumed more feed after 6 wk of age than calves that did not receive
lasalocid. However, at 1 to 4 wk of age, feed consumption was similar in both
groups of calves. Daily lasalocid intake from 2 to 4 wk of age was less than the
expected dose of 1 mg/kg body weight. However, after 6 wk of age because of
increased dry feed consumption, lasalocid intake averaged 1.5 mg/kg body weight.
Fecal scores of calves were not affected by the treatment. Also, fecal
examination at 4, 8 and 12 wk of age revealed no evidence of coccidiosis in calves
of either group.
Table 1.
Composition of Pre-starter diet
a
Ingredient
%
Drie% whey
46
23
19
7-60
Dried skim milk
Sodium calcinate
Lasalocid~
Additives
12
+ or +
~calfweena~ Merricks, Union center, WI.
A mixture of milk solids and fat containing 7% protein and 60% animal fat.
~pre-starter with lasaloci contained 88 mg lasalocid/kg.
Includes preservative, vitamins, minerals, and flavoring compounds.
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9
34
t'
Composition of starter dieta,b
Table 2.
Ingredient
%
Alfalfa, ground
Corn, cracked
Oats, rolled
Soybean meal
Molasses, wet
Dicalcium phosphate
Limestone, ground
25
30.1
20
18.4
5
.7
.3
.25
.25
+
+ or -
Salt
Trace mineral salt
c
Vitamins
d
Lasalocid
a As fed basis.
bpellet, 4.8 mm diameter.
c2200 IU vitamin A, 330 10 vitamin D, and 110 10 vitamin E per kg.
%tarter with lasalocid contained 44 mg lasalocid/kg.
Table 3.
Age
(wk.)
0
1
2
3
4
5
6
7
8
9
10
11
12
Body weight, weekly weight gain and feed intake, and daily lasalocid
intake of control or lasalocid-fed calves
Body weight, kg
Control Lasalocidfed
41.3
43.0
43.9
46.4
47.7
50.5
58.2
63.8
70.0
76.8
82.8
90.7
95.7
Weekly
weight gain, kg
Control
Lasalocidfed
42.0
44.5
45.1
47.7
49.2
54.It
60.8
67.7t
74.6t
81.5t
89.0*
96.2*
104.9**
1.6
.8
2.6
1.3
2.8
7.6
5.6
6.2
6.9
6.0
7.1
6.1
2.5
.5
2.8
1.4
4.9*
6.7
7.0t
6.9
7.0
7.3t
7.0
9.0**
Weekly dry
Lasalocid intake
feed intake, kg
Control Lasalocid- (mg/kg body
wt./day)
fed
.6
.9
2.2
4.5
6.9
9.9
13.2
16.0
17.5
18.8
20.0
22.2
.4
.7
1.7
4.4
8.0
11.6t
14.7
17.6
20.0t
22.8*
23.6*
24.61
1.0
.7
.4
.7
1.1
1.4
1.4
1.5
1.5
1.6
1.5
1.5
tDifferent from control (P<.l).
* Different from control (P <.05).
**Different from control (P<.Ol).
t,·,
~
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35
,
t·
r)
I
a
•
EFFECT OF SUPPLEMENTAL POTASSIUM AND BUFFER
IN STARTERS FOR EARLY-WEANED CALVES
•
Paula Flynn, J.L. Morrill, 1
P.G. Reddy, and J.J. Higgins
Summary
Sixty Holstein heifers were used from birth to 8 weeks of age to study the
effect of amount of potassium (K) in the diet and of adding a buffer to the
starter. Starters were formulated with and without 1% trona, a natural ore buffer,
at K concentrations of .9, 1.25, and 1.5% of the dry matter. To supply adequate
fiber, yet allow form ulation of the starter containing .9% K, 20% prairie hay was
included. All calves were fed milk and a prestarter, using an early weaning
procedure. Growth and feed consumption data and evaluation of health and
metabolic activity were used as response criteria. Overall, calves fed 1.25% K
consumed the same amount, whether fed buffered or nonbuffered starter. At other
K levels, calves fed nonbuffered starters consumed more. Growth of calves fed
buffered starter with 1.5% K was dept·essed. Metabolic data supported the
conclusion that this buffer was not beneficial with this type of starter. Increasing
the amount of K did not significantly increase calf response, but there was a trend
for gains to increase as K increased to 1.25% in both buffered and nonbuffered
starters. Since these calves were not heat stressed, opportunity for maximum
benefit from added K did not exist.
Introduction
Although potassium is the third most abundant mineral in the animal body
and has many vital functions, little research has been done on the K requirements
of calves. The National Reseat'ch Council currently recom mends K at .8% of ration
dry matter for all dairy animals. Recent research suggests that K requirements of
dairy cows are increased during hot weather. In general, forages are good sources
of K, thus high roughage diets usually contain ample amounts, but high concentrate
diets may benefit from supplemental K.
Using an early weaning program developed here at Kansas State, we have
observed rapid development of rumen fermentation and a beneficial effect of
addition of buffer to the starter ration. For years, sodium bicarbonate has been
the buffer most commonly used in feeds for l'Uminants. Recently, several new
buffers have become available for use. One of these is trona, a natural ore and
thus economical, which is supposed to have characteristics similiar to sodium
bicarbonate; however, little information is available concerning the use of this
buffer in diets for dairy animals.
I Dept . of Statisti cs.
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36
The objective of this study was to determine the effects of different
amounts of K and of use of trona in starter diets for early weaned dairy calves.
Procedures
Sixty Holstein heif er calves were used from birth until 8 weeks of age.
They were balanced according to time of birth and assigned to one of six rations.
The starter fed to half of the calves contained 1% of the trona buffer. The
remaining calves were fed non-buffered starters. Within each group, the starters
were formulated to contain either .9%, 1.25%, or 1.5% K, using potassium chloridp.
Hnd potassium sulfate to supply supplementary K. Other minerals were balanced
equally as nearly as possible. To control composition of feed consumed, hay and
concentrate were mixed together, and the resulting starter was pelleted. To allow
formulation of the starters containing the lowest amount of potassium, it was
necessary to limit the amount of alfalfa to 5%; prairie hay was used at 20% of the
starter mixture.
After receiving colostrum for 3 days, all calves were fed milk at 8% of
birth weight daily until 3 weeks of age in two daily feedings. For 1 week, they
were fed milk once daily at 4:} of birth weight, then weaned. To encourage them
to eat dry feed, a prestarter was provided until they consumed .5 lb prestarter
daily, then .5 lb prestarter was mixed with all the starter they would consume
each day until they were 6 weeks of age.
Daily feed consumption and weekly body weight gains were recorded. Fecal
consistency scores and general appearance ratings were recorded twice daily.
Blood samples were collected at 2, 3, 4, 6 and 8 weeks of age to allow evaluation
of the metabolic status of the animals.
Results and Discussion
The amounts of weight gained and of feed consumed are shown in Table 1.
Feed consumption and weight gains were depressed, compared to our usual results.
This happened partly because the prairie hay, which was used because it was lower
in K than alfalfa, was not as palatable as alfalfa. Overall, the amount of dietary K
had no significant effect on weight gains or feed consumed when calves were fed
the nonbuffered starters. There was a trend for weight gains to increase as K
concentration in feed increased. Among calves fed buffered starters, those fed
starters containing the most K gained the least. That group consumed less starter
than calves fed the other levels of K, but the differences were not statistically
si gnificant.
After week 1, when starter consumption was very low, calves fed
nonbuffered starter consumed more feed each week than calves fed buffered
starter, with the differences being significant (P<.05) during weeks 6, 7 and 8
(Table 2).
2Calfweena, Merricks.
4
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37
Fecal consistency scores were not affected by treatment (Table 1).
Results of analyses of blood
without significant effect on blood
excess, and those values listed are
in general, the calves were not
buffer would be of less benefit.
samples are shown in Table 3. Treatments were
pH, bicarbonate (HeO ), eo content, or base
within normal range. These ~ata indicate that,
experiencing metabolic stress and, therefore,
Potassium concentrations of red blood cells (Table 3) decreased with age,
but were not affected by amount of K in the feed.
Results of earlier studies have suggested that addition of buffer to calf
starters would be beneficial, and earlier' results here at Kansas State have
suggested that this would be especially true in our early weaning program. It is
known that buffers will be less beneficial in diets that contain more roughage than
in low roughage diets. The diets that we fed contained 25% hay, thus reducing the
need for a buffer. Apparently in this study, the starter was less palatable than
starters usually used here, so feed consumption was lower, probably rumen
fermentation was less active, and the need for a buffer was reduced. Thus, the
lack of a beneficial effect of a buffer in this stUdy does not suggest a general
recommendation against use of buffers in calf starters.
Very few of the calves in this study were subjected to heat stress. Had that
been the case, perhaps the higher concentrations of potassium would have been
beneficial. The data are not conclusive in showing a K need greater than .8% of
the dry matter. Most diets containing significant amounts of forages will supply
more than this amount.
Table 1.
Item
Mean weekly weight gains, feed consumed. and fecal consistency scores a
Nonbuffered Starter
1.5% K
1.25% [{
c
6.6 + .13 c 6.4 ~ .13 bc
Weight gain, Ib
c
Feed consul)!ed, Ib 16.9 + .88 16.1 + .86
Fecal score
1.1 +" .04
1.1 +" .04
a
.9% [{
bc
6.2 + .13
c
16.9 + .88
1.2 +" .04
bi'fJean ~ SEe
d' Means within rows with unlike superscripts differ (P<.05).
1 = normal to 4 = watery.
t'
I~'
Buffered Starter
1.25% K
1.5% K
b
5.7~.13b
13.9 + .95
1.2 +" .04
c
6.6 + .13
bc
16.1"+ .95
1.1 +" .04
.9% K
c
6.4 .!. .13
15.2 + .95 b
1.1 +" .04
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a
38
Table 2.
Effect on buffer on feed intake, (lb.)
Week
Nonbuffered Starter
1
1.32
1.98
4.62
9.46
2
3
4
5
6
7
Buffered Starter
1.32
1.76
4.4
8.8
17.6
b
24.4
b
29.5
b
33.0
19.1
a
31.9 a
a
27.7
8
37.2
a,bMeans within a row with different superscripts differ (P<.05).
Table 3.
Mean blood gas, pH, and red blood cell potassium concentrations
Item
Nonbuffered Starter
1.5% K 1.2596 K .9% K
pH
pC0 (mmHg)
2
Base excess (meq/L)
HCO (meq/L)
Red ~lood cell K (%)
7.371
52.49
4.55
29.27
.178
7.372
50.86
4.18
28.78
.188
7.372
52.75
4.87
29.58
.172
Buffered Starter
1.5% [{ 1.25% K .9% [{
7.372
52.82
4.84
29.69
.179
7.373
52.84
4.89
29.57
.203
7.370
52.56
4.48
29.23
.174
f·-
c
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39
a
••
USE OF EXTRUDED SOY FLOUR
IN MILK REPLACERS FOR CALVES
D.P. Dawson, J.L. Morrill, 1
P.G. Reddy, and K.C. Behnke
Summary
Oil-extt'acted, desolveritized soy flour without additional heat treatment
was used to prepare protein supplements for calf milk replacers by extrusion
processing. Various combinations of temperature, moisture, calcium concentration,
sulfur, and acid were used to prepare 32 different products. These products were
tested for trypsin inhibitor and antigenic activity and the most promising one was
chosen for further testing. This product alone or with supplementary amino acids
or amino acids and citric acid was used to provide 70% of the protein in
experimental milk replacers. These replacers were compared to an all-milk
replacer, using growth and metabolic responses of young Holstein bull calves. The
extruded soy protein was inferior to milk protein but calf performance was
sufficient to indi ca te a potential for this kind of product in areas where milk
products are prohibitively expensive. Amino acid supplementation of this soy
product was not beneficial. Acidification had some benefit in the young «3 week
old) calf, but was not beneficial later.
Introduction
In many countries, milk is not produced in adequate amounts to meet the
demand for human consumption. Even in areas where it is possible to increase milk
production, maximum returns result when milk is used to supply food for humans.
Thus, it would be desirable to have a feed containing no milk products for young
calves and use all saleable milk products for human food. Milk replacers are
available for feeding calves but the best ones use protein and carbohydrate orily
from milk, and all contain a large amount of milk products. Certain non-milk
sources of fat are efficiently used by calves and milk carbohydrate (lactose) is
readily and economically available in the United States from dried whey, but milk
protein has proved to be especially difficult to replace. Most of the non-milk
protein in milk replacers is from soybeans. The economical products usually give
poor results and even the more expensive products do not give results as good as
milk protein. Many human food products are made using extrusion processing of soy
protein. It seemed possible that the increased temperature, high pressure, and large
shear forces involved in extrusion processing might destroy trypsin inhibitors and
antigenic activity of soybeans and be an economical way to improve their use by
calves. This experiment was designed to test that hypothesis by producing many
different products and evaluating them, with or without further supplementation,
for use in calf milk replacers.
IDepartment of Grain Science and Industry.
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40
Procedures
Oil-extracted, desolventized soy flour was used as the raw material. This
flour was processed, with or without various additives in different combinations, in
a Wenger X-20 extruder. The additives were calcium chloride, fumaric acid, and
organic sulfur. The extruder was operated to provide different temperatures and
amounts of steam added in the barrel. The various combinations used resulted in
the production of 32 different products. These products were tested for content of
trypsin inhibitor and certain soy antigens. One sample had very low trypsin
inhibitor acti vity and no activity for antigens tested and was chosen for further
evaluation. Soy flour prepared under the same conditions as this sample was used
to supply 70% of the protein in an experimental milk replacer. In two other
experimental replacer's, this soy flour was supplemented with .7% lysine and .7%
methionine or with those amino acids and 1% citric acid. Those replacers were
compared to a milk replacer containing all milk protein, using neonatal Holstein
bull calves in a growth and nitrogen balance study.
Results and Discussion
The 32 products produced contained trypsi n inhibitor at various
concentrations between the original 147 units/mg and zero, and glycinin and
B-conglycinin activity from 0 to 85% of the original. The sample chosen contained
1 unit/mg trypsin activity and no activity for antigens tested.
Calves fed the all-milk replacer (control) grew faster throughout the 6
weeks of the experimental period. Calves fed the experimental soy flour without
additives lost weight between 1 and 2 weeks of age but during the last 4 weeks
gained almost as much as the calves fed the control replacer'. Those calves fed
experimental soy flour supplemented with amino acids and citric acid gained
slightly between 1 and 2 weeks of age but grew at a slower rate than those fed
the control or experi mental replacer without supplements during the remainder of
the experiment. The calves fed experi mental mi lk replacet' with amino acids only
lost considerable weight from 1 to 2 weeks of age and finished with lowest weight
of any group.
t
Feces of calves on control milk t'eplacer were mot'e liquid during the second
week of the experiment than feces from other calves, possibly because the mineral
content of the replacer was higher. Other data collected supported the growth
data and suggested that, while inferim' to milk protein, the experimental soy flour
has potential for supplying protein for calf milk replacers in areas where milk
proteins are unavailable. Amino acid supplementation was not beneficial but
acidification was beneficial during the first 2 weeks of life.
t·
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41
1£
•
EFFECT OF RUMINAL PROTOZOA ON
PERFORMANCE OF EARLY-WEANED CALVES
•
K.L. Anderson, T.G Nagaraja, J.L. Morrill,
P.G. Reddy, T.B. Avery, and N.V. Anderson
Summary
Twenty newborn bull calves assigned to two groups, protozoa-free or
protozoa-inoculated, were used to determine the effects of ruminal protozoa on
performance of early weaned calves. Calves in the protozoa group were inoculated
via stomach tube with a suspension of ruminal protozoa at weekly intervals until a
viable population was established. Calves were evaluated weekly for weight gain
and feed intake. Feed intake and weight gain were not significantly different
between the groups but tended to be higher in protozoa-inoculated than protozoafree calves.
Introduction
Calves weaned early consume dry feed at an earlier age than conventionally
weaned calves. This accelerated dl'y feed consumption contributes to an earlier
ruminal microbial development. We have determined that adequate bacterial
populations are present in the rumen of calves at a very early age, and subsequent
bacterial development is stimulated by incl'eased dry feed consumption. However,
no ruminal protozoa were detected in the calves weaned early, perhaps because
those calves were isolated from adult ruminants. Ruminal establishment of protozoa
in the young ruminant appears to require some form of physical contact with adult
ruminants.
Because common dairy management practices include ralsmg calves in
relative isolation from mature ruminants, calves may likely remain protozoa free
for many weeks. It is not known what influence protozoa may have on growth of
newborn calves. Therefol'e, we investigated the influences of protozoa on growth
and performance of early weaned calves.
Procedures
Twenty newborn, Holstein bull calves were separated from their dams within
24 h postpartum and placed in individual calf hutches. Calves were assigned to two
groups, protozoa-free and protozoa-inoculated, and physical contact of calves
between groups was prevented. Colostrum was fed to all calves until 3 d of age,
and then whole milk (8% birth wt.) was fed until calves were weaned at 3 wk of
age. Calves in both groups were fed a prestarter diet from day 3 until they
reached a daily intake of 227 g. They were then fed a mixture of 227 g of
prestarter daily and all the calf starter (2) they would eat until 6 wk of age, after
which they were given ad libitum access to only the starter diet. Beginning at 1
wk of age, calves in the faunated group were ruminally inoculated via stomach
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Q
42
tube with a suspension of ruminal protozoa. The inoculation was repeated weekly
until a viable ruminal protozoa population was established. This required up to 6
wk for many of the calves. The protozoal suspension was prepared from ruminal
fluid collected from a steer fed 50% grain and 50% alfalfa diet. The rumina] fluid
was strained through a layer of cheesecloth and 1500 ml was mixed with 750 ml of
mineral buffer (pH 6.8) and .1% oxytetracycline in a 2 1 separatory funnel, and
incubated at 39 C. After 1 h of incubation, the white layer of protozoal sediment
was removed and suspended in mineral buffer and inoculated into the rumen.
t·
Results and Discussion
Although calves were gi ven a heavy inoculum of protozoal suspension,
repeated administration was required to get the protozoa established in the rumen.
In most calves, protozoa were consistently present only after 5 wk of age (Table
1). Possibly, this was due to unfavorable conditions in the rumen of young calves.
The ruminal protozoal numbers tended to increase weekly after 6 wk of age (Table
1). Because many calves did not have a viable population of protozoa until 6 wk of
age, performance data of calves from 6 wk of age are presented.
Calves inoculated with protozoal suspension consistently had higher body
weights and feed intake, and in most instances, higher weekly weight gain than
protozoa-free calves; however, differences were not significant (Table 2). Previous
research has shown that ruminal protozoa may have positive, negative, or no effect
on weight gain and performance of ruminants. These conflicting data on the role of
ruminal protozoa have remained largely unexplained. Apparently, there are several
factors, or a combination of factors, that determine effects of protozoa on
performance.
Table 1.
Age, week
Ruminal protozoal
suspension
counts
in
calves
Number per gram of
ruminal fluid
1
o
2
3
88
44
180
40
140
4
5
6
7
8
195
668
9
460
10
11
12
inoculated
448
626
132.3
with
protozoal
t,
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43
Table 2.
~"
t
Age,
wk
0
6
7
8
9
10
11
12
Weekly body weight, weight gain, and feed intake of protozoa-free or
protozoa-inoculated calves
Body weight, kg
Weekly feed intake, kg
Weekly weight gain, kg
protozoaprotozoaprotozoaprotozoa- protozoaprotozoainoculated
inoculated
free
ft'ee
free
inoculated
41.0
56.2
62.6
69.0
75.7
84.0
91.9
100.5
41.2
60.8
68.0
74.2
80.9
87.1
96.7
106.1
4.1
6.4
6.3
6.7
8.4
7.9
8.6
5.8
7.2
6.2
6.7
6.2
9.5
9.6
10.7
13.1
15.3
18.4
20.9
23.2
24.7
12.3
15.2
17.3
18.3
21.1
24.0
26.3
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44
••
EVALUATION OF A CALF STARTER SUPPLEMENT
•
J.L. Morrill and P.G. Reddy
Summary
An experimental calf starter made from a pelleted commercial type
supplement and feeds readily available on the farm was compared to a conventional
pelleted calf starter in an attempt to demonstrate an economical alternative to
com mercial calf starter. Calves fed the eKperi mental starter consumed as much
starter and gained as much weight as calves fed the conventional starter, thus
demonstrating a potential for savings on feed cost. The project is continuing in an
attempt to improve the starter composition.
Introduction
A dairy calf starter usually contains several ingredients, including grains,
protein supplements, molasses, and vitamin and mineral supplements. It may also
contain hay, a buffer, an ionophore, some types of medication, and other
ingredients. Because of the many ingredients involved, most of which are used in
very small amounts, dairymen often purchase complete calf starters, even though
the grains, whi ch make up a major part of the starter, may be readily available on
the farm. If they could purchase in one mixture all of the needed supplements and
mix this on the farm with their own grains, a reduction in feed cost should be
possible. To facilitate proper mixing and to avoid fine particle size in the finished
feed (which calves do not like), the supplement mixture should be pelletted. The
purpose of this study was to formulate and test such a pelleted supplement
mixture.
Procedure
Twenty eight Holstein or beef crossbred calves were assigned to one of two
groups at 1 day of age. Assignments were made so that the groups were balanced
with respect to breed and sex. All calves were fed colostrum during the first day
of life, than transition milk for 2 days, each at 8% of birth weight. They were
then fed milk at 8% of birth weight daily in two equal feedings until daily dry feed
consumption was 1.3% of birth weight, then milk was fed at 4% of birth weight
once daily, then the calves were weaned. The calves were fed an all-milk
prestarter until consumption was 0.5 lb daily, then a mixture of 0.5 lb prestarter
daily and all the starter they would consume until they were 5 weeks of age. From
then until the calves were 8 week$ of age, when the experiment ended, they could
consume calf starter ad libitum.
Calves in one group were assigned to a control calf starter (Table 1). This
starter has been used in several experiments and has given good results, thus, it
Q
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45
was used for comparison. Calves in the other group were fed the experimental
starter. General appearance and fecal consistency scores were recorded for all
calves twice daily, and the calves were weighed weekly. Amount of dry feed
consumed was recorded daily.
Results and Discussion
.-
j'
Starter consumption and weight gains are shown in Table 2. Fecal
consistency and general appearance scores did not differ between groups. Although
Holstein bulls fed experimental starter consumed more starter and gained more
weight than control calves, little significance can be attributed to these
differences because of the small numbers involved. An appropriate conclusion is
that the calves fed the experimental starter performed at least as well as calves
fed the control starter. This demonstrated that the supplement mixture can be used
successfully when mixed with home-grown grains, molasses, and hay pellets, all of
which the dairyman may have or can easily obtain in bulk quantities.
Some calves separated and left alfalfa pellets. Smaller sized alfalfa pellets
were not readily available but an experiment is underway to determine the effect
of using 1/4 inch pellets that have been rolled to make the particle size of the
entire starter more uniform and eliminate sorting. For those desiring to do so, the
alfalfa pellets could be left out of the mixture. Expecially if that is done, the
calves should have access to hay.
Table 1.
Ingredient composition of calf starters
Ingredients
Corn, rolled
Oats, rolled
Sorghum grain, rolled
Alfalfa hay, ground
Alfalfa hay, pelleted
Soybean meal
Molasses, dry
Molasses, liquid
Dicalcium phosphate
Limestone, ground
Salt
Salt, trace minzral
Vitamin premix
3
Supplement mixture
~pelleted, 3/16 inch.
Conventional
30.00
20.00
7.50
25.00
1
(%)
Experimental (%)
34.00
15.00
25.00
10.00
5.00
8.00
.70
.30
.25
.25
1.00
18.00
Supplied 100,000 IV of vitamin A, 15,000 IV vitamin D/pound premix in ground
3corn cal'rier.
Contained (%): Soybean meal, 92.8; sodium bicarbonate, 2.5; dicalcium phosphate,
1.64; trace mineral salt, 1.48; limestone, 0,62; micronutrient premix, 0.96.
Micronutrient premix supplied (per pound of supplement mixture): Vitamin A, 5,680
IU; vitamin D, 810 lU; vitamin E, 142 lU; lasalocid, 62 mg. Pelleted, 3.16 inch.
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46
Table 2.
Total starter consumption and body weight gains of calves
Calves
1
Holstein bulls
Holstein heif ers
Beef crossbred
Number
of Animals
Starter consumption (lbs)
Weight gain (Ibs)
Control
Experi mental
Control Experi mental
8
14
75.9
91.5
6
51.8
106.8
91.6
58.3
55.1
54.6
45.3
82.5
56.5
43.2
lStarter consumption and weight gains were greater (P<.05) with Holstein bulls fed
experimental starter than Holstein bulls fed control starter.
._---._-
~---_._---
F
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47
a
RUMENSIN FOR THE LACTATING DAIRY COwl
•
J.C. Kube, R.A. Frey, and J.E. Shirley
•
Summary
Two Holstein cows were fed Rumensin for 12 weeks, beginning
approximately 90 days postpartum. Milk production increased 7%, whereas
percentage fat in milk decreased 10.3%. Percentage protein in milk increased 9.6%
in the early stages and decreased 10.2% in the late stages of the study. Daily fat
yield did not change, whereas protein yield increased in the early stages, but did
not change in later stages. Fat corrected milk (FCM) did not change with
treatment, but dry matter intake (DM 1) tended to increase when Rumensin was fed.
Acetate concentration did not change whereas propionate concentration increased,
causing a significant decrease in ruminal acetate:propionate ratio. Rumen pH
showed a nonsignificant numerical increase.
Introduction
Rtmensin, an ionophore, is used in the beef industry to increase efficiency
of gain. Rumensin affects the microflora in ruminant animals by shifting the
population to a higher proportion of propionate-producing bacteria. Normally, this
is not desirable in lactating cows because of the negative effect that high rumen
propionate concentration has on fat content in the milk. This was a preliminary
study to determine the proper dose of Rumensin prior to examining the effect of a
combination of Rumensin and bovine somatotropin on milk production when
treatments will begin shortly after peak lactation.
Procedure
Two third-lactation Holstein cows were ruminally fistulated and housed in
tie stalls. At approximately 90 days in milk, Rumensin was added to the diet in an
increasing and then decreasing step-wise fashion as follows:
Week
Week
Week
Week
Early
1 = 0 Rumensin
2 = 150 mg/day
3 = 300 mg/day
4 = 450 mg/day
Week
Week
Week
Week
Late
9 = 450 mg/day
10 = 300 mg/day
11 = 150 mg/day
12 = 0 mg/day
Week 5-8 = maintained on high (450-600 mg/day) level of Rumensin. Ruminal
samples were collected three times per week during weeks 1-4 and weeks 9-12.
Results and Discussion
Milk production data are presented in Table I and ruminal traits and DMI
are summarized in Table 2.
1Rumensin® is an experimental product not approved by the U.S. Food and Drug
Administration (FDA) for use in lactating dairy cows.
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~
i
48
Table 1.
Effect of level of Rumensin on various milk traits
Trait
Milk yield Ob/day)
Fat (%)
Fat Ob/day)
F.e.M. (Ib/day)
Protein (%)*
Protein (Ibs/day)*
Level of Rumensin (mg/day)
150
300
Stage
o
Early
Late
Early
Late
a
41.6
a
3.88
1.59
40.4
a
2.80
a
3.24
a
1.22
1.22
b
44.0 b
3.48
1.52
40.\
3.0 b
3.04
b
1.41
1.22
450
b
44.1 b
3.57
1.55
40.8 b
3.07 b
2.91
b
1.40
1.25
b
44.5 b
3.59
1.57
41.1 b
3.04
b
3.00
b
1.43
1.23
a,bYalues in same row with different superscripts are different (P<.Ol).
*Stage by treatment interactions. Listed by stage.
Table 2.
Effect of level of Rumensin on various rumen traits
Traits
o
Level of Rumensin
150
300
450
Rumen pH
Acetate (mmole)
Propionate (mmole)
Aceta te: Propionate
OMI
5.42
69.6
a
21.2
a
3.33
30.2
5.96
68.9
23.5
3.00
33.2
6.27
70.1
b
27.0 b
2.68
38.5
6.32
72.1
23.7
3.06
39.8
a,bYaIues in same row with different superscripts are diffel'ent (P<.OI).
Milk production traits (yield, % fat, % protein, lb protein) changed
significantly at the initial (150 mg) level of Rumensin but did not change
thereafter.
Propionate concentration increased and acetate:propionate ratio
decreased as the level of Rumensin increased. Plausible explanations for these
results include: l) The increase in propionate concentration in the rumen resulted
in an increase in the rate of milk and milk protein synthesis, while fat synthesis
did not change. This would explain why fat percent decreased while daily milk fat
yield did not change. 2) Rumensin is noted to have a protein-sparing effect that
may have caused an increase in protein synthesis in the mammary gland during
earlier lactation. In the later stages, glucogenic (glucose-like) nutrients were in
adequate supply, removing the benefits of ['umensin and causing no change in
protein yield. 3) These changes may be from the benefit of Rumensin as a
coccidiostat. The initial level of Rumensin may have eliminated subclinical
coccidiosis, allowing the cows to produce more milk.
t-1
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49
a
•
GLUCOSE. STARCH, AND DEXTRIN UTILIZATION
IN THE SMALL INTESTINE OF STEERS
• . K. Kreikemeier, D.L. Harmon'IT.B. Avery~ and
R.T. Brandt, Jr.
Summary
Holstein steers (775 Ibs) were surgically fitted with abomasal and ileal
cannulae, portal and mesenteric venous catheters, and an elevated carotid artery.
These steers were used to study starch digestion in the small intestine. Glucose,
corn starch, and corn dextrin were infused into the abomasum at various levels and
ileal digesta samples were collected. Disappearance of carbohydrate (CHO) in the
small intestine was determined using Cr:EDT A as an indigestible marker. Blood
samples were collected from the portal vein and carotid artery during carbohydrate
infusion. Blood flow was determined, and net glucose absorption across the small
intestine was calculated. Glucose infusions resulted in higher arterial glucose
concentrations and increased net glucose absorption than either starch or dextrin
infusions. Increasing infusion rates above 20 glh for both starch and dextrin
resulted in no further increases in net glucose absorption. Even though the
enzymatic processes for starch and dextrin hydrolysis became saturated at a low
infusion rate, the amount of starch and dextrin disappearing in the small intestine
increased with higher infusion rates. This was accompanied by an increased volatile
fatty acid (VF A) concentration in the ileal fluid with starch and dextrin infusions,
but not when glucose was infused. Data from these experiments support two
concepts:
(1) microbial fermentation is involved in small-intestinal starch
appearance and (2) starch and dextrin hydrolysis in the small intestine of steers is
more rate limiting than glucose absorptive capacity.
Introduction
Feed grains are composed of about 70% starch, and because of the amount
of grain fed, starch is the primary energy source in the diet of lactating dairy
cows. Digestion of starch can occur either by microbial fermentation in the rumen
and hindgut, or by enzymatic hydrolysis in the small intestine. Total tract starch
digestion in dairy cows ranges from 80-95% and is affected by grain type, as well
as processing method. Overprocessing of grain will increase its digestibility, but
may result in reduced fiber digestion, lower milk fat, and increased potential for
acidosis. Underprocessing, however, results in decreased starch digestion and poor
feed efficiency. Starch hydrolysis in the small intestine of dairy cows may be
beneficial. Increased glucose absorption (versus VF A production) may promote milk
production as well as lowering the incidence of ketosis in dairy cows. However, as
the amount of starch escaping ruminal fermentation increases, so does fecal starch
excretion. This indicates that small-intestinal starch digestion becomes limiting in
ruminant animals. Therefore, a series of experiments was conducted to evaluate
small-intestinal starch digestion and to determine factors that may be limiting.
1 Southwest Kansas Branch Exp. Sta., Garden C·lty, KS .
~artment
of Surgery and Medicine
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50
Procedures
Two groups of four Holstein steers (group 1, 660 lbs; group 2, 890 lbs) were
surgically fitted with abomasal and ileal cannulae, portal and mesenteric catheters,
and an elevated carotid. A temporary catheter was placed in the carotid artery
during sampling periods. Glucose, corn starch, and corn dextrin were infused
abomasally at 0, 20, 40, and 60 g/h. Ileal digesta samples were collected, and
disappearance of CHO within the small intestine was determined with Cr:EDTA as
an indigestible marker. Simultaneous blood samples were collected from the portal
vein and carotid artery, and glucose absorption across the small intestine was
calculated. Portal blood flow was determined by a primed continuous infusion of
para-amino-hippuric acid (PAH) into a small mesenteric vein.
Two experiments were conducted with the first group of steers. Glucose
(exp l) and corn starch (exp 2) were continuously infused into the abomasum at 0,
20, 40, and 60 g/h for 10 h. Steers were infused with 250 ml of solution per hour,
consisting of tap water, CHO, and Cr:EDTA. Steers were fed chopped alfalfa hay
at 1.5% of body weight (dry matter basis). Animals and treatments were
randomized to an 8-period crossover design for each experiment. During the
infusion period, 7 ileal digesta samples and 5 sets of blood samples were collected
from each steer. Ileal digesta was analyzed for VF A concentration, dry matter,
starch, glucose, and chromium. Plasma samples were analyzed for glucose and PAH.
The second group of steers was infused with glucose (exp 3), corn starch
(exp 4), and corn dextrin (exp 5). Infusions, digesta and blood collections, lab
analysis, and animal care were identical to those in experiments 1 and 2. Animals
and treatments were randomized to a 4 x 4 Latin square design for experiments 3
and 4, whereas experiment 5 was an 8-period crossover design.
Results and Discussion
Exp. 1. Steers consumed 9 lbs of alfalfa hay daily (dry matter basis) during
the glucose infusions (table 1). Increasing levels of abomasal glucose infusion
resulted in glucose passing the ileum into the large intestine, yet there was no
change in ileal fluid VF A concentration. This indicated that there was little
microbial fermentation of glucose in the small intestine.
Arterial glucose
concentration as well as net glucose absorption continued to increase with higher
glucose infusions. The amount of glucose absorbed was approximately equal to the
amount of glucose disappearing in the small intestine.
Exp. 2. Steers consumed 7.25 Ibs. of alfalfa daily (table 2). Even though
corn starch was infused, both free glucose and starch passed the ileum. The
amount of starch that escaped small intestinal digestion increased with increasing
amounts of starch infusion. In addition to starch passing the ileum, there was a
continual increase in ileal fluid VF A concentration. This indicates that smallintestinal starch digestion included microbial fermentation. Arterial glucose and
net glucose absorption increased as the infusion rate was raised from 0 to 20 g/h,
with no additional change with increased levels of infusion. It appears that the
process for small-intestinal starch hydrolysis became satuI'ated at the 20 g/h
infusion level.
t!
s
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51
The results of experiments 3 and 4 (tables 3 and 4) conducted with group 2
steers are similar to trends observed in the first 2 experiments. The final
experiment (table 5) was the infusion of corn dextrin. Dextrin is partially
hydrolyzed starch, consisting of straight chain glucose polymers with an average
chain length of 17 glucose units. By infusing dextrin, we eliminated any granular
characteristics as well as branch points that are found in starch. These
characteristics may limit enzymatic hydrolysis of the starch granule. When corn
dextrin was infused, steers consumed 11.5 lbs of alfalfa hay daily. At higher levels
of infusion, free glucose as well as dextrin flowed past the ileum to the large
intestine. There was an increase in ileal fluid VF A concentration, whereas arterial
glucose levels and net glucose absorption both plateaued at the 20 g/h infusion
rate.
Regardless of the type of CHO infused, increased infusion rates resulted in
increased amounts of small intestinal disappearance. When glucose was infused,
most of the disappearance could be accounted for by glucose absorption. With
starch and dextrin infusions, arterial glucose and glucose absorption plateaued at
20 g/h infusion rate. This was accompanied by a continual increase in ileal fluid
VF A concentration. Therefore, it is probable that a large amount of starch
digestion in the small intestine is by microbial fermentation. It also appears that
enzymatic processes responsible for starch and dextrin hydrolysis are more rate
limiting than the glucose absorptive capacity of the small intestine.
"t
Table 1.
Effect of abomasal glucose infusions on small intestinal disappearance
and net portal glucose absorption (Exp. 1)
Infusion rate, g/h
20
40
Item
0
Daily feed, lbs
Glucose flowiW past
ileum, g/h a
VF A in ileal fluid, mM
a
Arterial glucose, mM
Net portal glucose
a
absorption, g/h
9.2
9.7
9.2
8.6
0.4
0
20.8
4.1
0.8
21.3
4.5
8.0
22.0
4.6
20.6
21.3
5.0
1.5
1.5
0.1
-2.5
13.4
18.2
34.2
5.5
aLinear effect P<.Ol, bQuadratic effect P<.01.
60
SE
1
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52
Table 2.
Effect of abomasal starch infusions on small intestinal disappearance
and net portal glucose absorption (Exp. 2)
Infusion rate, g/h
20
40
Item
0
Daily feed, lbs
Glucose flow\rg past
ileum, g/h
Starch flowin p8st
ileum, g!h Ab
VF A in ileal
fluid, mM a
Arterial glucose, mM a
Net portal glucose
absorption, g/h a
7.5
7.5
6.6
7.5
0.4
0
0.5
0.9
1.1
0.1
0
1.3
13.3
26.2
1.8
23.3
4.1
26.2
4.3
28.9
4.4
30.2
4.3
1.9
0.1
-5.7
5.0
2.1
6.3
3.2
60
SE
aLinear effect P<.05, bQuadratic effect P<.05.
Table 3.
Effect of abomasal glucose infusions on small intestinal disappearance
and net portal glucose absorption (Exp. 3)
Item
Daily feed, Ibs
Gl ucose flowing past
ileum, g/h a
VF A in ileal fluid, m~
Arterial glucose, mM
Net portal glucose
absorption, g/h a
aLinear effect P<.Ol.
0
Infusion rate, g/h
40
20
60
SE
12.5
L3.0
10.4
12.3
1.3
0
23.9
4.4
0
25.8
4.9
4.90
27.9
5.1
13.8
20.5
5.1
2.8
2.8
0.1
-7.3
19.8
20.0
36.6
7.9
.,s-----------------
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I
53
Table 4.
Effect of abomasal starch infusions on small intesti nal disappearance
and net portal glucose absorption (E xp. 4)
Item
0
Daily feed, lbs
Glucose flowing past
a
ileum, g/h
Starch flowinR past
ileum, g/h
VF A in ileal fluid, mM
Arterial glucose, mMa
Net portal glucose b
absorption, g/h a
Infusion rate, g/h
20
40
60
SE
11.9
13.2
13.2
13.0
0.9
0
0.7
2.3
2.7
0.5
0
26.9
4.1
5.5
30.9
4.2
10.9
29.8
4.3
26.1
29.6
4.4
4.1
2.3
0.1
-6.7
8.5
12.0
12.1
1.9
aLinear effect P<.Ol, bQuadratic effect P<.Ol.
t
Table 5.
Effect of abomasal glucose infusions on small intestinal disa ppear ance
and net portal glucose absorption (E xp. 5)
Item
Daily feed, lbs
Glucose flowiM past
a
ileum, g/h
VF A in ileal
a
fluid, mM
ab
Arterial glucose, mM
Net portal glucose b
a
absorption, g/h
0
Infusion rate, g/h
20
40
60
SE
11.0
13.2
9.9
16.6
1.4
0
0
0.4
1.0
1.3
22.3
4.3
24.7
4.6
22.4
4.7
30.7
4.6
3.2
0.1
-7.3
14.4
14.3
9.4
4.6
aLinear effect P<.05, bQuadratic effect P<.05.
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54
1C
•
RELATIVE FEEDING VALUE OF THREE FORAGE-BASED
DIETS FOR HOLSTEIN HEIFERS
•
J.E. Shirley, J.L. Morrill, and W.H. Carinder
Summary
Soybeans interseeded with grain sorghum and harvested as a mixed forage
silage crop can be used successfully as a feed for growing dairy heifers. However,
daily gain is greater when grain sorghum silage plus alfalfa hay or prairie hay
supplemented with milo grain and soybean meal is fed.
Introduction
Replacement heifer programs should be cost effective but yield a heifer
large enough to be bred to calve by 24 months of age and with a well developed
mammary gland relatively free of internal fat. A daily gain of 1.6 to 1.8 lbs
appears to be optimum to achieve the desired bodyweight to be bred by 14 months
of age. Feed cost to achieve the above physical goals often accounts for 60% of
the total cost in a replacement heifer program. Forage may constitute the majority
of a heifer's dry matter intake during the growing phase, if it supplies adequate
energy, protein, mineral, and vitamins.
Grain sorghum silage and prairie hay are abundant feed sources in Kansas
and are frequently used in the diets of replacement heifers. However, grain
sorghum is relatively low in protein, deficient in calcium, low in potassium, and
potentially adequate in energy for growing heifers diets, whereas prairie hay is
adequate in potassium, low in calcium and phosphorus, marginal in protein, and low
in energy. Soybeans are well adapted to Kansas conditions and offer a forage that
is abundant in protein, calcium, and potassium but relatively low in energy and
phosphorus. Silage composed of a mixture of soybeans and grain sorghum should
provide sufficient protein, energy, calcium, phosphorus, and potassium to meet the
needs of growing dairy heifers. This trial was designed to ascertain the value of
soybean-grain sorghum silage relative to sorghum silage or prairie hay as a feed
for growing dairy heifers.
Procedures
Seventy-two Holstein heifers were sorted into light and heavy weight groups
and distributed among treatment groups according to age and body weight.
Treatment groups were soybean-grain sorghum silage (S-GSS), grain sorghum silage
plus alfalfa hay (GSS-AH), and prairie hay (PlI). Each treatment group contained
two replications (one light and one heavy), with 12 head per replication.
Forages were supplemented with milo and soybean meal in a ratio to
provide isocaloric and isonitrogenous diets. Calcium, phosphorus, potassium, trace
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55
mineral salt, and Rumensin were balanced across treatment groups. Trace mineral
salt was also provided free choice.
i·'
:t
All animals were introduced to the appropriate treatment for 1 week prior
to the experiment. Heifers were fed to gain 1.6 Ibs per day over the 97-day
experimental period. Experimental rations (Table 1) were adjusted for growth one
time during the trial. Ten percent feed above requirements was fed daily to
provide room for growth between the major feed adjustment periods.
I
"
Soybeans and grain sorghum were interseeded at the rate of 100 lbs of
soybeans and 20 lbs of grain sorghum per acre with a grain drill. The mixture was
harvested when the grain sorghum I'eached the early dent stage and ensiled in a
concrete stave silo until fed.
Table 1.
Experimental rations
Treatment
l
Light Heifers 2_
4
5
ON!
As Fed
.
HelOfers_
3
Heavy
DM
As Fed
- - - - - - l b s per head per day·------
A. 8-GSS
Soybean-G. ~org. Silo
Milo carri er
13.0
2.41
26.26
2.74
16.45
1.74
33.24
1.98
B. GSS-AH
Sorghum sil.
Alfalfa hay
Milo carrier
Oicalcium phosphate
Calcium carbonate
Potassium chloride
7.50
6.61
1.10
.05
.008
.04
17.13
7.72
1.25
.055
.009
.044
10.45
1.10
3.30
1.95
.077
.055
.286
12.0U
1.25
3.75
2.19
.077
.055
.286
8.63
8.27
1.10
.063
.0275
.088
19.72
9.66
1.25
.066
.0275
.088
C. PH
Prairie hay
Milo carrier
Milo
Soybean meal
Oicalcium phosphate
Calcium carbonate
Potassium chloride
12.30
1.10
3.21
2.28
.077
.066
.341
14.13
1.25
3.65
2.56
.077
.066
.341
1Rations shown are the initial rations which were adjusted to allow for increased
heifer wieght over time.
2Light heifers - initial weight less than 700 Ibs.
3Heavy heifers - inital weight greater than 700 lbs.
4DM
5As
= dry matter basis.
fed = as fed basis.
6Nlilo carrier - ground milo was used as a carrier for rumensin, salt, and vitamins.
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56
Results and Discussion
Holstein heifers fed grain sorghum silage plus alfalfa hay gained more
weight per day (2.2 lbs) than those fed prairie hay plus milo grain and soybean
meal (2.0 100) or soybean-grain sorghum silage alone (1.5 lbs; Table 2). However,
heifers fed soybean-grain sorghum silage appeared to increase in wither height
more than heifers on the other diets. This suggests that sufficient nutrients were
available in the soybean-grain sorghum diet to support a desirable growth rate
without excess body fat accumulation. Apparently, the additional body weight gain
(above 1.5 Ibs per day) observed in heifers fed grain sorghum silage plus alfalfa
hay and those fed prairie hay supplements with milo grain and soybean meal was
due to fat accumulation rather than skeletal growth.
Data in this report are from one study and will be supplemented with an
identical study during the winter of 1987-88. Conclusions drawn at this time are
preliminary and should be treated as such.
Table 2.
Weight gain and wither height change of Holstein heifers fed various
forage-based diets for 97 days
Diet
Daily Gain
Change in
Wither Height
Soybean-Grain Sorghum Silage
1.5 lbs
1.5 inches
Sorghum silage plus alfalfa hay
2.2 Ibs
1.25
Prairie hay plus milo grain
and soybean meal
2.0 lbs
1.34
Q
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57
K
••
A LOOK AROUND THE DAIRY INDUSTRY:
BACKWARD AND FORWARD
C.L. Norton
A Look at the Past
It was the late President Harry Truman, renowned for his interest in
history, who said that those who ignore history are doom ed to reli ve it. Our
interest in dairy events of the past half century is to develop a base from which
to consider what we may expect in the next several decades.
Many of us have been privileged to have experienced some very remarkable
changes in agriculture, particularly in the dairy industry. Fifty years ago,
American agriculture was recovering from the effects of the dust bowl days and
record breaking heat, and breaking the grip of the depression. Federal government
agencies were set up to help deal with the dilemma (programs of Rooseveltls New
Deal):
the Works Progress Administration (WPA), Social Security, Rural
Electrification Administration (REA), and the Agricultural Adjustment Act (AAA).
At least two of these programs have had a lasting and telling effect on our
society.
In those days of the mid-30's, there were approximately 24 million U.S.
dairy cows that averaged 4,184 Ib of milk and 165 Ib of butterfat. The stage was
set for an historic period in American agriculture.
The following chronology is by no means complete, but many current
commonplace methods and practices originated or were in their infancy during this
time span:
1937 -
Federal Milk Marketing Orders were established, providing milk pricing
stability.
Field baling of hay was in its infancy.
1938 -
The Commodity Credit Corporation (CCC) bought butter.
Hybrid seed corn was becoming available.
A forage field chopper was marketed by the Fox Rivet' Tractor Company.
Artificial insemination in the U.S. was getting under way.
Elevated milking parlors were introduced.
1939 -
New York World's Fair. The Dairy Wol'1d of Tomorrow featured the
Borden Company Rotolactor.
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58
.l
.....1'
1940 -
The American Dairy Association (ADA) was formed in St. Paul, Minnesota.
The first mechanical barn cleaner was advertized.
The Purebred Dairy Cattle Association (PDCA) was formed in July at
Peterborough, N.H.
1941 -
Gonadotropic hormones were first used in the laboratory.
Blood typing was developed and implemented as a method to confirm
parentage.
1942 -
First uniform dairy scorecard was copyrighted by PDCA.
1944 -
The war years slowed progress.
The shift to bulk tanks began.
The number of u.S. dairy cows reached 25,661,000 - the greatest number
in history.
1945 -
Front end loaders on tractors appeared.
Penicillin and other antibiotics became available.
Urea was introduced as a protein substitute.
1946 -
Silo unloaders were being tested.
1947 -
Milk replacers were put on the market.
Thyroprotein experiments were being conducted in selected land grant
uni versities.
1948 -
The ring test, for
Minnesota.
1949 -
Pipeline milkers were used in California.
The Dairy Shrine Club was organized at Waterloo, Iowa.
AAA set the dairy support price at 75-90% of parity.
1950 -
The tax on
signature.
1951 -
The first calf resulting from embryo transfer was born.
The USDA was conducting long-term crossbreeding studies of dairy cattle.
1952 -
Dr. C.F. Huffman, Michigan State University, suggested the role of
microorganisms in ruminant digestion.
1953 -
The American Dairy Association (ADA) approved the year-round set aside.
1954 -
Landmark research on the control of mil k fever by feeding non-legume
hay during the dry period was reported.
Secretary of Agriculture Benson reduced dairy price supports to 75% of
parity.
colored
brucellosis was
oleo
was
perfected
eliminated
at
with
the University
of
President Truman's
,.,
J,..-,,"
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59
l~
I,-J'
1955 -
Benson ended the tie-up between Farm Bureau and Extension service
personnel.
1956 -
The USDA Animal Disease Laboratory was established at Ames, Iowa.
1957 -
The diet-heart controversy heated up because of the American Heart
Association claims against ani mal fats.
Herringbone milking parlors were reported in use in New Zealand.
1958 -
Herdmate comparisons replaced daughter - dam comparisons.
1959 -
"Cow pools" got a lot of press.
1960 -
Minimum tillage research was starting.
Forage testing was paying off for dairymen.
President Eisenhower signed a bill boosting the price support level from
$3.06 to $3.22 per cwt.
Liquid manure handling works for hogs, why not dairy cattle?
1961 -
The outlook was for a yearly U.S. production of 127 billion Ib of milk. If
butter consumption were at the 1935-39 level, 155 billion Ib would be
required.
DHIA average production: 10,327 lb of milk; 401 lb of fat. For the first
time, the national average exceeded 400 lb.
Free-stall housing was initiated in state of Washington.
1962 -
Trend towards heavier grain feeding intensified.
1963 -
Naturally proven sires were giving way to carefully selected young sires.
The idea of cow leasing got attention.
Rubber mats in tie stalls saved bedding costs.
1965 -
Cow index was used to rank cows.
Electronic data processing was established on dairy records.
National DHIA was organized.
1967 -
Techniques for synchronizing estrus was developed.
"Standby pool" of milk pricing was proposed.
Wisconsin legislature approved allowing oleo manufacturers to use yellow
color.
President Johnson signed a bill curbing dairy imports.
1968 -
"Repeatability factor" was first used in bull proofs.
Dairymen, Inc. and Mid-America Dairymen cooperatives were created.
1969 -
The Holstein Association approved the red and white herdbook and
permitted the registration of 110ff-coJor l1 black and whites.
1971 -
PD Dollars was the new USDA-DHIA index for ranking AI bulls.
i
---------------------------41
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60
1972 -
California set 8.7% non-fat solids standard for whole milk.
Teat dipping and dry cow treatment were initiated to help control
mastitis.
Mechanized feeding came to stall barns.
Prostaglandin was developed to control the cow's estrous cycle.
1973 -
Conclusion on dairy crossbreeding: don't do it.
VOlA streamlined national dairy promotion efforts by placing National
Dairy Council (NDC) under the same umbrella as American Dairy
Association (ADA) and Dairy Research, Inc. (DRINC).
Bovine ova transfer became available on a commercial basis.
Calf hutches were widely accepted.
1974 -
Hoard's Dairyman editorial sounded the alarm for increased farm debt,
which had jumped at a great rate. It said many dairymen would benefit
from sound counseli ng on their fi nancial a ff airs.
1975 -
Modified Contemporary Comparison (MCC) replaced Herdmate Comparison
in determining Predicted Difference (PD).
Oleo controversy was over; Minnesota and North Dakota removed tax.
Beecher Arlinda Ellen established a new world record for milk production:
50,314 lb in 305 days.
1979 -
"On the farm computer" began to become a part of the dairyman's
management program.
Greater use was made of consultants on feeding, breeding, construction,
and use of fertilizers.
1981 -
Warnings appeared in the press to watch our financial health.
1982 -
Cheese yield pricing (component pricing) of milk was proposed.
Results of the use of bovine somatotropin (bSt) or bovine growth hormone
(bGH) were reported.
Bull proofs were updated with a new base because of genetic gain.
Imitation dairy products and imported casein continued to plague the
dairy industry.
1983 -
Biogas production (methane from manure) gained increased attention.
End-product pricing (equity pricing) of milk continued to progress.
President Reagan signed into law the Dairy and Tobacco Adjustment Act
(Milk Diversion Program), designed to cut milk production and lower milk
support program costs.
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~
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61
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.'.
1984 -
Contracts were signed by 37,888 dairymen to reduce production for 15
months. A 50¢/cwt assessment was established to finance incentive
payments.
The Dairy Promotion and Research Board was established; Ivan Strickler,
lola, KS was elected president, with a 36-person board of directors
composed of dairy producers; a budget was set at $130 billion; and a
15¢/cwt assessment was set.
DHI Quality Certification was implemented.
1986 -
Commercial domestic sales of dairy products increased significantly.
Agricultural exports suffered declines.
Farm credit agencies were in deep trouble.
Export of frozen embryos was an expanding industry.
1987 -
There were threats of international trade wars, which have a direct
effect on agricultural products.
A Look to the Future
In considering what lies ahead, one is reminded of the old saw about the
economist who was proud of the fact he'd predicted seven of the last two
recessions. Furthermore, our collective memory is usually so short that one can
predict almost with impunity what will transpire in the future.
1. Expect
to see much better management
management, labor management.
-
herd
2. Dairymen of the future will be more astute in finances.
those who were better financial managers.)
management,
financial
(The survivors will be
3. There will be greater use of higher PD bulls. Some breeders have been slow to
accept this philosophy, but not the more successful ones. "Using the numbers"
with good judgment will prevail.
4. Use of on-farm computers will increase.
computer feeding among the better herds.)
(There will be widespread use of
5. More extensi ve use will be made of consultants.
dairymen will pay retainers for -expert advice.)
(An increasing number of
6. There will be greater use of total mixed rations.
7. Use of by-pass protein will increase (based on protein solubility) for highproducing cows.
8. The use of bovine somatotropin (bSt) will have a modest impact on the dairy
industry.
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62
9. It will be a long time before the U.S. resorts to milk production quotas like
Canada and Europe. A two-price system may be acceptable
10. If the U.S. is to ever compete successfully in the world dairy economy, our
marketing aggressiveness and effectiveness must improve markedly.
11. Although it is unlikely to occur, the most effective way of improving U.S. milk
production efficiency would be for each dairy operation to be on a production
testing program.
12. There will be ample headroom in the average production per cow, partly
because of the continued reduction of support prices, which will reduce the
number of marginal dairy herds.
It
LLJi0ato---
P-p"-T
- -. . .
~-
.oj;
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63
••
USDA-DHIA SIRE SUMMARIES -
•
AI ADVANTAGE
E.P. Call
Summary
USDA-DHIA Sire Summaries are published semiannually and provide the dairy
industry with an accurate evaluation of the transmitting ability of bulls for milk
and milk components. Geneti c potential is established at the time of conception.
Therefore, current service sires represent the primary means of improving the
genetic base of the future herd. Based upon first evaluation of daughters of AI and
non-AI bulls, the data clearly indicate the genetic superiority of bulls selected by
the AI industry. Dairy producers are strongly urged to select service sires from the
Acti ve AI bull listi ngs.
Introduction
The need to progeny test dairy bulls to evaluate their transmitting ability
for production traits became apparent more than 50 years ago. Milk production is a
se~-limited trait (bulls don't give milk), and the heritability for milk is about 25%
(h =.25). Early methods to rank the genetic ability of bulls included simple
daughter averages adjusted for age and length of lactation and daughter-dam
comparisons. Both systems failed to accur'2te1y evaluate bulls, since environmental
influences accounted for about 75% (e =.75) of the variation among cows'
production. Artificial insemination (AI), high speed computers, and increased
enrollment of producers into the National Dairy Herd Improvement Program (NDHIP)
provided the mechanisms for the USDA-DHIA Sire Summary Program.
The Predicted Difference System
The Predicted Difference (PO) System provides the means to: (1) rank bulls
with one another and (2) estimate the inferiority or superiority of a bull's future
daughters compared with the genetic base (breed average). The current genetic
base is 1982 or PD82, which means that a zero bull (PO = 0) is an average sire for
two-year old cows calving in 1982. The equation used to calculate PD is:
PD82 = R(D - MCA + SMC) + (l-R)AM
Where: R = Repeatability or accuracy of the information, based upon no.
of daughters and distribution among herds.
D = Average production of daughters.
MCA = Average production of contemporaries or herdmates.
SMC = Average sire merit for contemporaries - adjusts for genetic
level of herdmates.
AM = Ancestor merit - adjusts for differences in genetic ability of
ancestors.
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Current information is available from http://www.ksre.ksu.edu.
-
-
64
EValuating Bulls Based Upon PD82
The July, 1987, USDA-DHIA Sire Summary serves as an excellent example
that real differences exist among bulls. The most accurate comparison of groups of
bulls is based upon the first evaluation, which involves two-year old daughters
without selection pressure that would occur later in the Active AI group. As shown
in Table 1, either within breed or among breeds, the AI group has a distinct
advantage overall. While the main advantage of the PD system is to rank bulls for
selection purposes, monetary benefits may also be estimated. For example, in Table
1, the average PD$ superiority of a daughter by an AI bull is + $56 compared to
the average daughter of a non-AI bull. This means that on average, daughters of
AI bulls will have $56 more milk sold for each lactation.
The AI advantage is even greater when the Active AI bulls are selected as
a group, as noted in Table 2. All breeds considered, the active AI bulls' daughters
are + $125 superior to the average daughters of non-AI bulls. These differences
are real and have economic impact on the dairy herd. Selecting bulls based upon
the PD system assures that the herd of tomorrow will be better genetically and
more profitable. Cows selected for milk production convert feed into milk more
efficiently.
Read More About It
1.
July, 1987.
Sire Summary List (DyS-2977). North Central Regional Publication 137.
Kansas State University. Manhattan (Extension Dairy Science).
2. Sire Evaluation Procedures for Yield Traits. NCDHIP Handbook. 1986.
Kansas State University, Manhattan (Extension Dairy Science).
Table 1.
Comparison of first-evaluation
non-AI sires. July, 1987.
AI-proved
bulls
with contemporary
Non-AI
Predicted Difference
M
%F
F
$
Breed
AI
Predicted Difference
%F
$
M
F
Ayrshire
Brown Swiss
Guernsey
Holstein
Jersey
+343
+271
+482
+436
+327
-.05
-.04
-.03
-.02
+.00
+ 6
+ 6
+19
+13
+16
+29
+24
+58
+46
+44
+105
- 32
-125
+ 4
-.05
+.01
+.00
+.00
-.01
-9
+6
-2
-4
-2
-19
+15
- 5
-14
- 3
All Breeds*
+432
-.02
+13
+44
-104
+.00
-4
-12
*No. of bulls: AI
= 706;
Non-AI
= 1,707
-71
t)
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65
Table 2.
Comparison of active, proved Al bulls with all non-AI sires. July, 1987.
AI
~_ t':-~
."
.
,--~
Breed
Predicted Difference
M
%F
F
$
Ayrshire
Brown Swiss
Guernsey
Holstein
Jersey
+432
+719
+756
+865
+764
-.03
-.01
-.04
-.01
-.03
+12
+27
+29
+30
+33
All Breeds*
+831
-.01
+29
*No. of bulls: Al
= 668;
Non-AI
Non-AI
Predicted Difference
M
%F
F
+44
+84
+89
+96
+95
- 79
-165
-151
-320
-176
-.03
+.01
+.00
+.01
+.01
- 7
- 5
- 7
-11
- 7
-15
-17
-20
-35
-22
+93
-291
+.01
-10
-32
= 13,118
I
'J
j
it
Charles
~ichaels,
Director of the Kansas Artificial Breeding
Service Unit (KABSU).
$
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66
,
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II
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,
••
EARLY LACTATION SOMATIC CELL COUNT
SHOULD BE LOW
J.R. Dunham
t;
Summary
Cows and heifers in milk for fewer than 50 days, as shown on the DHIA
Somatic Cell Count report, should have a lower average Somatic Cell Count than
cows in milk for more than 300 days, if the dry cow mastitis treatment and
management programs are effective.
Introduction
11
j
III
11
II'
II
The DHIA Somatic Cell Count (SCC) average for a dairy herd is a good
evaluation of a mastitis control program. Since leucocytes migrate to the mammary
system during periods of subclinical mastitis, the SCC average indicates the
amount of subclinical mastitis in a herd. A realistic goal for 8 herd average SCC is
less than 200,000.
In many herds with average SCC over 400,000, the average SCC of early
lactation cows is higher than that of late lactation cows. This indicates a problem
during the dry period, either dry cows are not being cured of mastitis or they are
becoming re-infected with mastitis during the dry period.
Evaluating the Dry Cow I;
'l!
I-:!
"
Mastitis Control Program
The DHIA SCC report summarizes the herd on each test day accordi ng to
the stage of lactation of each cow. This summary is the Days in Milk SCC Average
shown in Table 1.
j ••
Table 1.
Days in milk and Somatic Cell Count average
Days in Milk
Fresh
Fresh
Fresh
Fresh
Fresh
under 50 days
50 to 100 days
101 to 200 days
201 to 300 days
over 300 days
Your Herd
497,000
390,000
435,000
444,000
466,000
SCC Average
Mid-States Top 25%
178,000
159,000
166,000
183,000
206,000
<
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67
~.
I •
i
The effectiveness of a dry cow mastitis control program can be evaluated
by comparing the SCC average of cows fresh less than 50 days with that cows
fresh over 300 days. If this report shows a consistently higher average SCC for
early fresh cows, than an evaluation of the dry cow program should include:
1.
Drying Cows Off. Cows should be turned dry by discontinuing milking
abruptly. Those cows producing more than 40 lb at dry-off should be
fed less grain to decrease milk flow.
2.
Dry Cow Treatment. Every quarter should be treated with a dry cow
preparation shown to be effective by sensitivity tests. sanitary
procedures during treatment must be followed. Cows showing high see
during late lactation should be re-treated 10-14 days following dry-off.
3.
Lots and Housing. The lots and housing facilities must be clean and as
dryas possible for springing heifers and dry cows.
4.
Prepartum Milking. Springing cows and heifers making up udders that
show signs of mastitis should be milked prepartum, and a treatment
program should be initiated.
"
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68
••
UPDATE ON HEAT DETECTION AIDS
•
J.S. Stevenson and E.P. Call
Background
Poor heat detection is a major cause of reproductive failure in most dairy
herds. About one-half of the heat periods are undetected, resulting in prolonged
calving intervals. In many cases, the problem is serious enough that some producers
have compromised their breeding goals by utilizing natural mating exclusively or
maintaining clean-up bulls. The ['esult of these compromises means loss in genetic
superiority of future replacement heifers and the potential for serious injury or
death of farm help or family.
Heat Detection Aids
Several methods utilizing heat detection aids have been promoted to
improve the number of heat periods identified (efficiency) as well as to increase
the accuracy of heat detection. These methods have included various detection
aids (e.g., teaser animals, heat mount detectors, tail paint, and estrous
synchronization). Increased costs are associated with obtaining such detection aids
in addition to the cost of labor for visual observation and maintenance of
the aids. Better training of people and more frequent observation for heat will
increase heat detection rates. Aggressive teaser animals (vasectomized bulls or
hormone-treated steers or cows) promote or instigate estrous behavior and increase
detection rates compared with casual visual observation. However, hidden costs
associated with maintenance of teaser animals are real, and there is an increased
chance of injury in confined, concrete lots. Synchrony of estrus (e.g., by
PGF -alpha or its analogs) facilitates detection of more animals because of
incrJased mounting behavior of many cows or heifers in heat simultaneously.
Although supplementary use of heat detection aids might increase detection rate,
there is no substitute for careful observation. Since most mounting activity occurs
between 6 pm and 6 am, a minimum of two heat detection periods should be used.
Success in AI programs is achieved when at least one person is responsible for heat
detection.
Economic Evaluation of Detection Aids
Using selected references, a recent Texas study evaluated various detection
methods to determine the least costly ones. Summarized in Table 1 are expected
detection rates based on type of method and frequency of observation,
•
,.
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69
....
"
,i
"
Table 1.
Heat detection aids and expected detection rates 1
Detection
method
Teaser bull
Heat mount detectors
or tail paint
Prostaglandi ns
Prostaglandins +
heat mount detectors
Visual observation
Frequency of
observation
2
Expected heat
detection rate (%)
3X/day
2X/day
3X/day
2X/day
Casual
3X/day
2X/day
3X/day
2X/day
3X/day
2X/day
85-100
80-90
80-90
75-85
55-65
80-90
75-85
80-90
75-85
70-80
65-75
1Adapted from Holmann et al. (1987) J. Dairy Sci. 70:186-194.
2The dairy producer's ski 11 and attention to detail largely determine the
heat detection rate attained with each method.
Because there are different time committments and other costs associated
with the various detection methods, the preferred method depends on the value of
labor and the ability to achieve actual expected detection rates.
The study concluded that, if a producer believes the value of his labor is
greater than $2.25 per hour, heat mount detectors or tailhead painting would be
the methods of choice. If, however, the value of labor is less than $2.25, using
unaided, visual observation 3X/day would be the most economical.
In order for heat mount detectors to be more cost effective than tailhead
painting, they must increase detection rate by 10%. The above methods were 25 to
50% less costly than using a teaser bull or prostaglandins. The authors suggested
that only dairy producers who are extremely poor at managing the alternative heat
detection methods can justify the use of teaser bulls or prostaglandins as their
routine heat detection method. One cost variable not examined in this study was
the cost of the improved genetic gain that can result when groups of heifers are
synchronized with prostaglandi ns for convenience of insemination by superior sires
selected for calving ease. Costs of convenience are difficult to evaluate because
they often correspond to quality of life.
-.
'",".\1
Based on the results of the Texas study, break-even
that tail paint or heat mount detectors with routine
economical than unassisted visual observation under a
51tuations. The study concluded that a large proportion of
use unassisted visual detection methods because they place
estrous detection.
costs of labor suggest
observation are more
wide range of dairy
producers continue to
low value on labor for
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70
Ie
••
UPDATE ON GONADOTROPIN-RELEASING
HORMONE TREATMENTS FOR
REPEAT BREEDERS
J.S. Stevenson
Summary
In three of six studies involving over 1,650 cows, treatment of lactating
dairy cows with 100 Jlg GnRH (2 cc Cystorelin~) at the time of third or fourth
insemination improved conception rates by 12 percentage points. When all six
studies are considered, rates improved by 10 percentage points. These data provide
strong evidence for continued use of GnRH at the time of insemination for repeat
breeders.
Review of Experiments
Table 1 summarizes six published studies in which GnRH was administered
at repeat services. Three of the studies did not demonstrate significantly higher
conception rates after GnRH treatment, but two of these had a limited number of
cows. In the last study (Stevenson et al., 1987), the health status of cows was
known prior to treatment. GnRH was found to be equally effective for increasing
conception rates in cows with previous reproductive problems as it was in cows
with a normal health status, compared to untreated cows in each health status (see
pp 24-25 in this publication).
•
~
Some methodologies were different in the six studies. In most cases, GnRH
was administered immediately after insemination. However, in the study by
Pennington et a1. (1985), GnRH was given within 2 hI' of first detected estrus and
cows were inseminated at various intervals after GnRH. The timing of GnRH and
AI, relative to detected estrus, was varied in our early work (Stevenson et al.,
1984). In spite of these differences, positive effects of GnRH occurred at the
recommended dose of GnRH or Cystorelin® (l00 Ilg), when it was given at the time
of AI following third or fourth service.
Use of GnRH also increased conception rates of dairy cows at first and
second services in several studies. However, based on pI' eli minary work in Israel
(personal communication, Y. Folman), it appears that timing of GnRH
administration relative to the onset of estrus and the timing of insemination may
be critical to its potential success. We are continuing to study these variables in
our research. We suggest that the potential advantRges for using GnRH be
considered relative to its cost and the possibility of no positive response with
GnRH use at any service, because of presently unknown factors in some herds.
.'
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71
Table 1.
No. cows
studied
Conception rates of repeat-breeding dairy cows treated with GnRH
% pregnant
Control
GnRH
185
97
92
961
209
513
48
51
46
38
46
36
73*
66
55
47*
44
47*
2,057
40
50
Referenee
Lee et al. (1983) Am. J. Vet. Res. 44:2160.
Stevenson et a1. (1984) J. Dairy Sci. 67:140.
Pennington et al. (1985) Bov. Pract. 20:14.
Phatak et at (1986) Theriogenology 26:605.
Lewis (1987) J. Anim. Sci. 65(Suppl. 0:185.
Stevenson et a1. (1987) J. Anim. Sci. 65(Suppl 1):418.
Weighted average = +10% points
*Higher conception rates than control (P<.05).
/..
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72
K
••
COW-SIDE MILK PROGESTERONE TESTING
E.P. Call and J.S. Stevenson
Summary
Cow-side milk progesterone tests are effective in determining the presence
of an active corpus luteum (CL) on the ovary. The test is best used as an adjunct
to the Preventive Herd Health Program (PHHP) as a means of identifying cows that
have not yet been detected in heat and are candidates for synchronization with
prostaglandin (PGF). Several test kits are on the market, and all involve similar
chemical principles. However, each test has its own protocol, so read and follow
directions EXACTLY. A I1control l1 or "standard l1 sample must be run with each test
for comparison.
Introduction
Current technology provides procedures by which progesterone may be
estimated in blood or milk. Since progesterone is the product of the corpus luteum
(CL), such tests are of benefit in assessing the reproductive status of the cow, if
the procedure is cost-effective, reliable, and conducive to on-farm use. Such
I1cow-side l1 tests are available and in use. Success or failure of the tests depends
primarily on the 'way in which the results are to be used in management. For
example, if the test is to determine pregnancy with an accuracy greater than 90%,
the results will be disappointing. If the procedure is used to detect when a cow
should be bred, the producer will be misled.
When To Use Test
Cows not yet bred. The greatest benefit of the cow-side test comes from
evaluating the status of a cow not yet bred. For example, cows not yet serviced
by 60 days or so after calving have the potential of not conceiving by 85 days.
Since synchronization programs using prostaglandins (PGF) are effective if cows
have functional CLs, a positive progesterone test would identify such cows. The
alternative is to identify such cows via ovarian palpation ~ rectum. The
economic benefits are savings of $1.00 - $2.00 per day fol' cows that are open 85
to 115 days. Also, the avel'age hel'd calving interval may be reduced by one-half
day for each day the interval from calving to first service is shortened.
Table 1 suggests the chances of identifying cows with an active CL based
upon the stage of the 21-day estrous cycle. On the average, a cow will have
positive progesterone 62% of the time. When a negative test is obtained, another
test should be performed in 5-10 days. If the second test is negative, the cow
should be examined ~ rectum to determine ovarian status.
c
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73
Cows diagnosed cystic. Some cows have luteinized cysts that produce
progesterone. If the cow-side test were positive, then PGF could be administered
immediately. If the cyst were not luteinized, Gonadotropin-Releasing Hormone
(GnRH) or Cystorelin® would be used, followed in 10 days with PGF.
Pregnancy diagnosis. Cows with a positive progesterone test 21-23 days
after service have about 75% chance of having a terminal pregnancy. Conversely,
cows with a negative test at the same time have a 95% change of being open and
should be watched closely for signs of heat. The lowered accuracy (7596) of the
positive group results from embryonic abortion after 21-23 days and errors in heat
detection at the time of the service. The economic benefit from the cow-side test
3 weeks after service would corne from increasing heat detection pressure on those
cows suspected to be open.
Heat check - when to service. The cow-side test is NOT designed to
determine the best time for servicing the cow. Remember - the cow-side test only
indicates the presence or absence of a CL. Cows with a negative test should be
observed closely for signs of heat. As noted in Table 1, an open cycling cow is
expected to have low progesterone during 3896 (or 8 days) of the 21-day cycle.
Cows with low progesterone would be expected to have a functional CL within 10
days, but a cow-side verification test would be indicated before using PGF.
A Word About Synchronization
Using PGF to synchronize cows with active CL (positive progesterone) has
been shown to be effective about 90% of the time. However, only one-half of the
cows will be identified in standing heat within 3-4 days of PGF injection. These
cows, of course, should be bred according to normal procedures. Those cows not
detected in standing heat could be time bred at 72 and 96 hr after PGF. In rare
cases, such cows may show heat symptoms 5-7 days after PGF and should be
re-bred accordingly.
Table 1.
Chances of detecting progesterone in milJ.< in relation to
to the stage of the estrous cycle in cows
96 of estrous
cycle
Progesterone
in milk
1 to 4 days
19%
No
6 to 17
62
Yes
18 to 21
19
No
Days of
estrollS cycle
1Assumption is made that the cow is cycling and not pregnant.
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74
K
••
HOW IMPORTANT IS EXTRA SOLIDS-NOT-FAT
IN YOUR MILK?
B.A. Roberts
Introduction
Milk with high solids-not-fat is valuable to the consumer for its flavor and
nutritional value and to the manufacturer of milk products, especially relating to
cheese yield. Solids-not-fat consists of all solids in milk other than fat. Protein is
the most important component of milk because of its nutritional value and its
functional properties. Other components, such as milk fat and lactose, also
contribute to milk quality and impart certain characteristics to milk products but
to a lesser degree.
Milk Composition
The average composition of whole raw milk is:
Protein
Lactose
Fat
Ash
Water
Total
3.5%
4.9%
3.5%
0.7%
87.4%
100.0%
NOTE: The composition
information.
values
vary
depending
upon
the
source
of
Milk Fat
The major advantage of milk fat is the delicate, pleasant flavor it imparts
in fluid milk and other dairy products. Milk fat percentage shows a greater
variation than any other constituent in milk. There is a direct relationship between
the amount of fat and the amount of solids-not-fat in milk. As milk fat increases,
solids-not-fat also increases; however, this relationship is not in direct proportion.
In general, an increase of 1% in fat is accompanied by an increase of about 0.4%
in solids-not-fat of mixed, whole, raw milk.
Protein
Protein is an important element of the solids-not-fat portion of milk.
Approximately 80% of the protein in milk is classified as casein. Casein has many
functional properties in dairy products, such as cheese, and many other food and
non-food products. The remainder of the protein (approximately 20%) is whey
protein (lactalbumin), which remains in the serum after casein is precipitated.
f.~~
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75
This protein is found in whey during the cheese making operation. Both of these
proteins are of excellent quality, although we hear more about casein than whey
protein. It has been calculated that the protein in one quart of milk is
approximately equivalent to the protein in 5 ounces of meat or fish, 5 large eggs,
4 ounces of cheese, or 16 slices of bread. Milk protein contains most of the
essential amino acids needed for growth and maintenance of life.
Lactose
Lactose (milk sugar) is the principle carbohydrate and a major component in
milk. Lactose differs from other sugars, such as sucrose, in functional properties
because it has a low relative sweetness. It is about 20% as sweet as sucrose. A
number of benefits are derived from lactose in milk and milk products, but they
are not as well defined as those of milk fat and protein. It does playa significant
part in the overall good flavor of milk.
Ash (Minerals)
The mineral content of milk, especially calcium, is important nutritionally.
It is reported that milk and milk products provide about 75% of the calcium in the
human diet. Other minerals include phosphorus, magnesium, iron, iodine, sodium,
and potassium.
Importance of Components of Milk
Today greater emphasis is being
especially protein. Therefore, more and
utilizing component pricing of milk from
solids-nat-fat or protein. The importance
planned usage for that milk.
placed on the solids-nat-fat in milk,
more areas of the United States are
the producer, which considers fat and
of components of milk varies with the
Fluid Milk
The promoters of high-solid fluid milk look at the nutritional value and the
preference for the taste of fluid milk that has a high content of solids-not-fat.
Today, greater concern is placed on nutrition than ever before. In milk and other
dairy products, calcium and protein are the major constituents. Over the past few
years, there has been a gradual trend to consume less whole milk and more lowfat
milk. The need for calcium has been well documented because calcium deficiency
has been linked to the bone disease known as osteoporosis. Calcium also has been
suggested as a possible factor in the prevention of high blood pressure. The need
for protein is well established as a body-cell building block and an essential
component of overall nutriton. It is generally accepted that extra solids in fluid
milk, especially skim and lowfat milk, make a richer tasting drink. Proponents of
more solids in milk also support the opinion that high-solids milk sells better.
Opponents feel that the extra cost of fortified-solids milk would have a direct
effect on consumption.
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76
Manufactured Milk
For milk used in manufactured dairy products, a greater and more direct
effect can be realized by using high solids milk in most cases. Butter' production is
the exception, since only butterfat is used. In cheese making (hard and cottage
cheese), protein (casein) is the most significant milk component used. However, in
making hard cheeses, milk fat is also important. In the manufacturing of nonfat dry
milk and ice cream, all the solids-nat-fat portion of the milk is used. Quality and
yield of cheese are the two most important concerns of any cheese maker to
maximize his profits. Cheese yields (or the amount of cheese manufactured from a
given weight of milk) are directly related to the amount of protein (casein) in raw
milk. Thus, the cost of producing a pound of cheese is reduced if high-solids
(protein) milk is used, since fixed costs remain unchanged.
Read More About It
Campbell, John R. and Marshall, Robert T. 1975. The Science of Providing Milk
for Man. First Edition. McGraw-Hill Book Company.
Ladd, George W. and Dunn, John R. 1979. Estimating Values of Milk Components
to a Dairy Manufacturer. J. Dairy Sci. 62(11):1705.
Higher Milk Solids Debated.
Inc., March.
1986.
Dairymen's Digest, Associated Milk Producers,
.,
-."-
,-
...:..-
...
,<
-
--~
t,
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P
I
I
i
77
•
EMERGING PATHOGENS IN DAIRY AND FOOD PRODUCTS
D. Y.C. Fung
•
•
Summary
Most people working with dairy and food products are familiar with
pathogens such as Staphylococcus aureus, Salmonella, Clostridium perfringens, and
Clostridium botulinum. There are several new ones that may not be too familiar to
the general public. They are described in this summary.
Yersinia enterocolitica
Yersinia enterocolitica is a gram-negative, short, rod-shaped bacterium
found in animal intestines. It has been isolated from feces and lymph nodes of
healthy and sick animals and humans. It is also found in contaminated milk, cheese,
poultry and meat products, and seafoods. The organism can cause gastroenteritis. It
is destroyed by standard pasteurization. Since it is a psychrotroph, it is of concern
for refrigerated foods in general.
Campylobacter jejuni
Campylobacter JeJuni is a gram-negative, spirally curved, rod-shaped
bacterium. It causes abortion in cattle and is second only to brucellosis in terms of
economic loss to the farmer. It is claimed that this organism causes more cases of
gastroenteritis than even Salmonella. Foods incriminated include raw milk, pork,
ground beef, and poultry products.
Listeria monocytogenes
Listeria monocytogenes is a gram-positive, short rod. In humans, listeria
may produce meningoencephalitis with or without bacteremia. In one major
outbreak in 1985, 300 cases were reported with 85 deaths. The organism has been
found in cheese and meat products and is of great concern to the dairy industry at
this moment.
All these emerging pathogens are killed by proper cooking of food (for
example cooking meat to internal temperature of 70C for 10 min). The major
problems are recontamination of processed food and undercooking of food. Good
sanitation practices, proper food cooking, and handling will reduce greatly risks of
food poisoning by these and other pathogens in foods.
~------------------------w
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78
K
••
OFF-FLAVORS OF ULTRA HIGH TEMPERATURE
(OUT) TREATED MILK
.'
W.G. Ikins
Introduction
Ultra high temperature (OHT) treated milks are products that have been
subjected to temperatures greater than 130°C for at least one second. A UHT heat
treatment of 138°C for 2 seconds can be utilized to pasteurize milk, or in other
words to destroy all of the pathogens. This product is not microbiologically sterile,
but is thought to keep better than conventionally pasteurized milk. UHT sterilized
milk is treated with a more severe heat treatment to produce a product in which
all pathogens are destroyed and other microorganisms that may produce undesirable
changes during storage are inactivated. These milks receive a heat treatment
ranging from 130°C for 8 seconds to 150°C for 2 seconds.
UHT sterilized milk can be packaged aseptically in flexible cartons and
stored at room temperature for months. While this characteristic has made UUT
sterilized milk a popular product with consumers in Western Europe, the same
cannot be said for its commercial success in the U.S. Part of the reason for this
lack of acceptance is the different flavor of the high temperature treated milk.
•
•
Processing UUT Milk
The heating times of UUT processed milk are so short that an in-container
process is not possible. If the holding time of the milk at high temperatures is not
carefully controlled, the delicate flavor of the product will be greatly affected.
Therefore, a heat exchanger system in which the milk is in a continuous flow must
be utilized. There are two general types of heat exchangers: direct and indirect.
The direct heating of milk can be performed in two ways. With either
method, the milk is preheated indirectly by coming into contact with plates that
have been heated by the out-going product. Steam is injected into the product to
produce the desired temperatures. The second process involves the spraying of the
product into a chamber containing steam at the desired temperature. The
condensed steam dilutes the milk constituents and must be subsequently removed.
The milk is cooled from the sterilization temperature and concentrated by spraying
it into a vacuum chamber.
The indirect methods of producing UHT processed milk utilize corrugated
plates, tubes, or scraped plates to insulate the product from the heating medium,
which is usually steam or pressurized hot water. Once again, out-going product is
used to warm the in-coming product and the in-coming product is used to cool the
out-going product.
•
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•
79
The Flavor of UHT Milk
Some researchers have maintained that UHT milk has a purer flavor than
conventionally processed milk. It is true that some aromatic compounds in fresh
milk responsible for weedy, barny, or feedy odors can be removed during UHT
processing. This occurs when milk is sprayed into a vacuum chamber during the
cooling process. However, UHT milk still has two major flavor characteristics that
influence how consumers regard this product: cooked and stale flavors.
Immediately after processing, UHT milk has a cabbage-like odor, which
rapidly dissipates) giving way to a slight cooked flavor. The cooked flavor initially
present slowly decreases during the first 3 weeks following processing and then
begins to level off. Two weeks after processing, an unpleasant oxidized or stale
flavor can be detected and becomes progressively more obnoxious with the age of
the UHT milk.
The development of off-flavol's, especially stale and/or oxidized flavor, is
the most important factor limiting the acceptability of UHT milk. Stale flavor has
been described as a paintey, pastey, or cardboard-like defect. There is a great
deal of disagreement concerning the compounds responsible for stale flavor. In the
dairy chemistry laboratories at Kansas State, we are working on isolating and
identifying the compounds involved. In addition, we feel we have discovered a way
to greatly reduce the concentrations of these compounds in UHT milk. This project
has received a tremendous boost this summer with the acquisition of a mass
spectrometer, a sophisticated instru ment that fractures and identifies separated
chemical compounds.
Read More About It
1.
Mehta, R.S.
1980. Milk processed at ultra-high-temperatures.
review. Journal of Food Protection 43:212.
2. Bassette, R., Fung, D.Y.C., and Mantha, V.R. Off-flavors in milk.
Critical Reviews in Food Science and Nutrition 24 (1):1.
A
CRC
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a
80
K
••
RESEARCH IN PROGRESS
Double Inseminations and Cystorelin$ for
Repeat-Breeding Cows
J.S. Stevenson, J.F. Smith, and E.P. Call
Long-standing recommendations for improving conception rates in lower
fertility dairy cows have suggested that double breeding might increase conception.
However, little information exists to verify that recommendation. We have
demonstrated that these repeat-repeat breeders have increased conception rates
when CystoreIin® (l00 J.lg or 2 cc) is administered at the time of insemination.
Therefore, the objective of this on-going experiment is to test further the benefit
of single and double inseminations followed by Cystorelin® or no further treatment.
Cows with at least two previously unsuccessful inseminations will be eligible for
treatment in each of foUl' treatment groups:
1) single AI, 2) single AI +
Cystorelin®, 3) double AI (first AI at normal time and the second AI given 12 hr
later), 4) double AI + Cystorelin® after the first breeding. Upon concluding this
study, a recommendation for breeding repeat-breeders should be available.
t-,
Effect of Time of Adminstration of Lasalocid on Performance
and Ruminal Development of Early Weaned Calves
S. Pruitt, T.G. Nagaraja, J.L. Morrill, P.G. Reddy
T.B. Avery, and N.V. Anderson
Recent research at Kansas State University has shown the beneficial effect
of lasalocid in diets for early weaned calves. In that study, lasalocid was given in
milk during the first 2 wk of age, and thereafter, lasalocid was made available
through pre-starter and starter diets. Significant differences in feed intake and
weight gain between the lasalocid-fed and control group were apparent only after
5 wk of age. Therefore, it may be possible to obtain the observed benefit of
lasalocid through pre-starter or even starter diets. To determine the time of
administration of lasalocid to calves required to elicit the maximum benefit,
48 bull calves will be used. Calves will be assigned to one of four treatments: (1)
lasalocid fed in milk, pre-starter, and starter diets, (2) lasalocid fed in pre-starter
and starter diets, (3) lasalocid fed in starter diet only, and (4) no lasalocid in milk,
pre-starter, or starter diet. Four calves in each group will be ruminally cannulated
at 3 days of age. Ruminal samples from each calf will be collected at weekly
intervals from 1 to 12 wk of age to measure fermentative and microbial changes.
Feed intake, weight gain, and health of all calves will be monitored.
•
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~.-
81
Role of Ruminal Ciliated Protozoa in
Subacute Acidosis in Cattle
D. W. Goad, T .G. Nagaraja, and T.B. Avery
Grain overfeeding causes fermentation products of ruminal microorganisms
to shift from volatile fatty acid to lactic acid. Ciliated protozoa in the rumen may
have an important role in regulating starch metabolism because of their ability to
ingest starch and metabolize it slowly to volatile fatty acid, protecting it from
rapid bacterial fermentation to lactate. Six ruminally cannulated steers will be
assigned to one of two groups: faunated (a normal microbial population including
protozoa) or defaunated (a protozoa-free microbial population). The animals will be
overfed with an all-grain diet and ruminal samples will be collected to determine
pH, osmotic pressure, fermentation product concentration (lactic acid and volatile
fatty acids) and changes in microbial populations. Blood will be monitored for
changes in pH, blood gases, packed cell volume, and lactic acid concentration.
Comparison of ruminal changes in faunated and defaunated steers will indicate the
role of ruminal ciliated protozoa in starch fermentation and subacute acidosis.
Use of Progestins and Pulsatile GnRH to Reestablish Ovarian
Function in Early Postpartum Dairy Cows
M.O. Mee and J.S. Stevenson
On the average, dairy cows begin to cycle within 14 to 28 days after
calving, but are not observed in heat until 35 to 42 days postpartum. Subnormal
luteal function often occurs in cows during the natural resumption of ovarian
cycles. We are examining presently the effect of a short-term "priming" with a
progestin in combination with pusatile gonadotropin-releasing hormone (GnRH or
Cystorelin®) on the life span and function of the corpus luteum (CL) after an
induced ovulation. Blood samples will be used to examine hormone concentrations,
CL function, and duration of ovarian cycles. Our results should provide information
concerning the effects of progestin priming on the initiation of normal follicular
and luteal function and further understanding concerning the mechanisms
associated with the reestablishment of normal ovarian cycles.
Rumina! and Blood Changes Associated with Induced
Subacute Acidosis in Cattle
D.W. Goad, T.G. Nagaraja, T.B. Avery, and D.L. Harmon
Subacute or "chronic" acidosis occurs when animals are deprived of a grain
diet for some time and begin refeeding suddenly or when the proportion of grain
consumed increases in relation to the roughage level. Unlike acute lactic acidosis,
the symptoms of subacute acidosis are subtle; ru men pH decreases slightly and
ani mals tend to go off feed or have reduced intake resulting in decreased
performance. Six ruminally cannulated steers fed either a high grain (80%) or a
high roughage (80%) diet will be over'fed with an all-grain diet to determine the
changes that occur in the rumen and blood during subacute acidosis. Ruminal
samples will be collected to measure pH, osmotic pressure, and fermentation
products (lactic acid and volatile fatty acids). Starch-fermenting and lactic
acid-utilizing bacteria and ru men ciliate protozoa will be enumerated to determine
microbial population changes. Blood samples will be analyzed for pH, blood gases,
packed cell volume, and lactic acid concentration.
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82
Thyroidal Imbalances and Effects on Reproduction
and Nutrition in Holstein Heifers
•
R.E. Stewart, M.O. Mee, and J.S. Stevenson
Conception rates and estrous behavior in cattle decrease during the hot
months of the year, possibly because the cows become hypothyroid. Hypothyroidism
in cows has been associated with increased late abortion, stillbirth, and weak
calves; retained placentas; and decreased milk production. Removal of the thyroid
gland inhibits libido in bulls and estrous behavior in cows without altering gamete
production. Feeding thyroprotein restored sexual behavior in both sexes.' We plan
to conduct preli minary experi ments using Holstein heifers. Estrous cycles of the
heifers will be synchronized using two injections of PGF 2-alpha. Heifers will be
housed indoors in tie stalls and have a catheter inserted in the jugular vein. Using
automatic infusion pumps hooked to the catheters, saline, propylthiouracil, and
thyroxine will be infused continuously over approximately 40 days (starting at
estrus following synchronization) causing heifers to be euthyroid, hypothyroid, or
hyperthyroid. Heifers will be moved into outside pens and watched for estrus at
least 4X daily from day 17 to day 22 of the cycle. Pedometers also will be used
during the duration of the experiment to record daily activity. Feed intake and
body weight will be measured daily, and feed/gain ratio will be calculated. Daily
blood samples will be collected and assayed for progesterone, thyroid hormones (T 4
and T3)' thyrotropin (thyroid-stimulating hormone or TSH), estradiol, and
testosterone. This preliminary work will document the effects of hypo- and
hyperthyroidism on estrous behavior, weight gain, daily activity, and hormonal
concentrations in heifers.
•
Effect of Acidification of Milk Replacers on Nitrogen
Utilization by Young Calves
P.G. Reddy, J.L. Morrill, and J.P. Smith
It has become common in recent years to acidify calf milk replacers to
decrease pH from about 6.4 to about 5.3. The original reason was primarily to
prevent spoilage when milk replacers were fed ad libitum to groups of calves.
There is some indication that acidification will increase utilization of milk
replacers, regardless of how they are fed; however, there are insufficient data
regarding this question. It is possible that response from acidification will depend
on the type of milk replacer, e.g., whether it does or does not form a curd in the
abomasum. Thus, the objective of this study is to determine the performance and
nitrogen retention by calves fed either sweet or acidified milk replacers based on
dry skim milk or on whey protein concentrate.
Day-old Holstein bull calves are moved to a metabolism crate, fed colostru m
for 3 days, and then assigned to one of the experi mental replacers. At 2 1/2 and 5
1/2 weeks of age, nitrogen retention is being determined by total collection of
feces and urine for 3 consecutive days. Fecal scores and general condition
evaluations are being recorded at each feeding time. Calves are weighed weekly.
.'J#!
•
,..
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83
Effect of Lasalocid in Ration for Growing Heifers
J.L. Morrill, D.E. Isbell, and P.G. Reddy
Lasalocid is a polyether ionophore antibiotic that is cleared for use in
rations for growing dairy heifers. Potential advantages of lasalocid include a
beneficial shift in production of ruminal volatile fatty acids, an increased ruminal
protein bypass, control of coccidia, and a beneficial effect on mineral metabolism.
However, more information is needed concerning the effect on response of young
heifers. A study in progress is examining the effect of lasalocid on growth, feed
consumption, rumen metabolism, and body composition of heifers from 10 to 24
week of age.
Lymphokine-Activated Killer Cells: Efficacy in Bovine
Herpesvirus Type-l Induced Respiratory Disease
l
2
P.G. Reddy, F. Blecha , J.L. Morrill, and H.C. Minocha
Our recent research with bovine recombinant interleukin-2 (rIL-2) showed
that calves receiving rIL-2 and bovine herpesvirus-type 1 (BHV-I) vaccine
withstood a challenge with BHV-l much better than calves receiving vaccine alone.
Serum neutralization titers to BHV-l were increased sixfold in calves vaccinated
and treated with rIL-2 compared to calves that were only vaccinated (70 vs 427).
However, even though the dose of r1L-2 that we used (25 \lg/kg of body weight for
5 days) clearly had a positive effect on the health of the calves, the lymphokine
treatment did produce some serious side effects. Calves receiving r1L-2 became
anorexic, developed diarrhea, and exhibited a mild fever. One to two days after
the rIL-2 regimen, the adverse side-effects abated. Therefore, the objective of the
present research was to determine the dose of rlL-2 that enhances the animal's
ability to resist a BHV-l challenge without causing any side effects.
Twenty-five 4- to 6-month-old calves were allotted by weight to one of
five treatment groups:
a control and 4 levels of rIL-2. At the start of the
experiment (day 0), all calves were vaccinated with a modified-live BHV-l
commercial vaccine. Calves received their respective dose of r1L-2 on days 0, 1, 2,
3, and 4.
On day 20, all calves will be challenged with SHV-L
Lymphokine-activated killer cell cytotoxicity against BHV-l infected target cells,
lymphocyte proliferative response to phytomitogens, interleukin-2 production from
concanvalin A-stimulated lymphocyteE, and antibody response to BHV-l will be
determined on days 0, 5, 15, 20, 23, 26, and 29. Shedding of BHV-l in nasal
secretions will be determined from days 20 to 29. Clinical assessment of calves
will be conducted throughout t he experiment.
~Anatomy and Physiology.
Laboratory Medicine.
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84
•
The Livestock and Meat Industry Council, Inc. is a nonprofit, educational,
and charitable corporation, which receives and distributes funds that play an
important role in programs of the Department of Animal Sciences and Industry. The
council is controlled by industry people. Funds generated by the LMIC help
accomplish many teaching and research goals.
Funds contributed to the Council are deposited with the Kansas State
University Foundation and are used as directed by the Council's Board of Directors
or by its Project Review Committee.
Donors receive credit from both
organizations.
Officers and Board of Directors of the LMIC are: Fred C. Germann
(President); Stan Fansher (Vice President); Calvin L. Drake (Executive Vice
President); Bill Amstein (Secretary); Charles N. Cooley (Treasurer); and Raymond
Adams, Jr., Harry Burger, Scott Chandler, Henry Gardiner, W.C. Oltjen, A.G.
Pickett, Floyd Ricker, Wayne RogIer, Duane Walker, and Gene Watson as Members
of t he Board.
The Council's indi vidual projects are numerous. The LMIC recently funded
research in the Departments of Agricultural Engineering and Animal Sciences and
Industry to stUdy sulfur dioxide as a grain preserva ti ve. Funds from the Harry
Burger Student Enrichment Fund help support the dairy judging team. The LMIC
helped fund the research that led to the development of lasalocid by scientists in
the Department of Animal Sciences and Industry.
•
If we are to continue research, our industry needs to supplement state and
federal funds. Our industry needs to help support its own research and teaching
programs to train tomorrow's industry leaders.
The LMIC is asking stockmen, agribusinessmen, and friends of the livestock
and meat industry for liberal contributions. Gifts can be cash, livestock, other
gifts-in-kind, and land. Land gifts can be set up as a unitrust that affords the
donor a tax deduction and provides for a life income. This offers you the
opportunity to invest in your future and in your children's future. All contributions
are tax deductible and all contributors become Council members. Checks should be
made to the KSU Foundation, LlVIIC Fund and mailed to:
Livestock and Meat Industry Council, Inc.
Call Hall, Kansas State University
Manhattan, KS 66506
The
Livestock
&
Meat
Industry
Council,
Inc
•
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85
•
ACKNOWLEDGEMENTS
Appreciation is expressed to the following organizations for their support of
dairy research at Kansas State University:
CEVA Laboratories, Inc., Overland Park, KS
Cooper's Animal Health, Kansas City, 1'110
Eli Lilly and Company, Greenfield, IN
Hoffmann-LaRoche, Nutley, NJ
International Minerals &: Chemicals Corp., Mundelein, IL
Jackson Ice Cream, HutChinson, KS
Kansas Agricultural Experiment Station, Manhattan, KS
Kansas Artificial Breeding Service Unit (KABSU), Manhattan, KS
Kansas DHIA, Manhattan, KS
Livestock Meat Industry Council (LMIC), Manhattan, KS
Merrick's, Union Center, WI
Milk Specialities, Inc., Dundee, IL
The Upjohn Company, Kalamazoo, MI
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Appreciation
Kansas Agricultural
Meyer for typing
photography, and to
is expressed to Eileen Schofield, Associate Editor of the
Experiment Station for editing, to Kathy Minneman and Brenda
the contents of this publication, to Len Harbers for the
Fred Anderson for the cover design ~yith Joan Istas' photo •
The following Departments at Kansas State University are recognized for
their cooperation and contribution to our dairy research program:
Agronomy
Ana tomy and Physiology
Grain Science and Industry
Laboratory Medicine
Statistics
Surgery and Medicine
Contribution No. 88-114-S, from the Kansas Agricultural Experiment
Station, Kansas State University, Manhattan 66506. When brand names of products
are mentioned in a Kansas State University pUblication, no endorsement or
criticism of similar products not named is intended.
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
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Agricultural Experiment Station, Kansas State University, Manhattan 66506
Report of Progress 527
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October 1987 •
PUblications and pUblic meetings by the Kansas Agricultural Experiment Station are available and open to the public regardless of
race, color, national origin, sex, or handicap.
10-87-2.5M